Ice Age - Scholars

Gonzaga Debate Institute 2008 Scholars

1 Ice Age

Ice Age Disad Ice Age Disad .................................................................................................................................................................1 Shell................................................................................................................................................................................3 **********Uniqueness/Link**********.....................................................................................................................4 Uniqueness - IA Approaching.........................................................................................................................................5 Ext: GW  No Ice Age .................................................................................................................................................6 Increased Warming Key................................................................................................................................................11 **********IA Impacts**********.............................................................................................................................12 IA Impacts - General.....................................................................................................................................................13 IA Impacts – Species Extinction...................................................................................................................................15 IA Impacts – Disease.....................................................................................................................................................17 IA Impacts – War...........................................................................................................................................................18 IA Impacts – Famine.....................................................................................................................................................19 IA Impacts – Economy..................................................................................................................................................20 IA Impacts – Refugees .................................................................................................................................................21 IA Impacts – Storms .....................................................................................................................................................22 ***********Probability***********.........................................................................................................................23 Present Temp Drop .......................................................................................................................................................24 Empirical Evidence ......................................................................................................................................................25 Studies/Models Prove ..................................................................................................................................................26 Natural Phenomena ......................................................................................................................................................27 Solar Theory ...............................................................................................................................................................28 ***********Timeframe***********.........................................................................................................................30 Interglacial Period Now................................................................................................................................................31 Solar Patterns (2022).....................................................................................................................................................32 ***********Answers to Answers***********..........................................................................................................33 AT: Warming Outweighs...............................................................................................................................................34 AT: GW  IA (Milankovitch Proves)..........................................................................................................................36 AT: GW  IA (Volcanoes)...........................................................................................................................................37 AT: GW  IA (Little Ice Age)......................................................................................................................................38 AT: GW  IA (Solar Patterns).....................................................................................................................................39 AT: NAC Shutdown (General)......................................................................................................................................40 AT: NAC (Keenlyside Model)......................................................................................................................................41 AT: NAC (Cooling Inev.) .............................................................................................................................................42 AT: NAC (Wind-cycles)................................................................................................................................................43 AT: NAC (Solar Inactivity) ..........................................................................................................................................44 AT: NAC (Studies) .......................................................................................................................................................45 AT: NAC  IA............................................................................................................................................................46 AT: Polar Precipitation .................................................................................................................................................47 AT: Milankovitch Wrong..............................................................................................................................................48 ***********AFF ANSWERS***********...............................................................................................................49 GW  Ice Age (Stagnant NAC)..................................................................................................................................50 GW  Ice Age (NAC)..................................................................................................................................................54 NAC Brink....................................................................................................................................................................55 NAC - Most Detailed Studies Prove.............................................................................................................................56 NAC Impacts- General..................................................................................................................................................57 NAC Impacts – Species Extinction (Plankton).............................................................................................................58 NAC Impacts – Species Extinction (Arctic).................................................................................................................59 NAC Impacts – Salinity Valves ....................................................................................................................................60 NAC Impacts – Methane Calthrates ............................................................................................................................61 NAC Impacts – Larsen B. Iceshelf...............................................................................................................................62 NAC Impacts – El Nino................................................................................................................................................63 NAC Impacts – Famine ................................................................................................................................................64 NAC Controls Climate..................................................................................................................................................65 NAC Controls Ocean Conveyors..................................................................................................................................66

Gonzaga Debate Institute 2008 Scholars

2 Ice Age

NAC Controls Hydrologic Cycle..................................................................................................................................67 **********2AC (w/ specific extensions)**********................................................................................................69 2AC- General Block .....................................................................................................................................................70 2AC - Volcanoes Turn...................................................................................................................................................74 Ext. SO2 cools ..............................................................................................................................................................77 2AC - Polar Precipitation Turn ....................................................................................................................................80 Ext. GW  PP..............................................................................................................................................................81 Ext. Ice Age = Inevitable...............................................................................................................................................82 Polar Precipitation = Inevitable.....................................................................................................................................83 2AC – Glacial Melting Turn.........................................................................................................................................84 Ext. Ice Melt  IA ......................................................................................................................................................86 **********1AR General Extensions**********.......................................................................................................88 1AR- Ext. GW fails.......................................................................................................................................................89 1AR- Ext. Need to Stop GW.........................................................................................................................................90 1AR- Ext. GW makes conditions worse.......................................................................................................................91 1AR- Ext. NAC changes=man made ...........................................................................................................................92 1AR- Ext. Credible Ev. ................................................................................................................................................93 1AR- Multiple tipping points........................................................................................................................................94 1AR- TF Defense .........................................................................................................................................................95 1AR- Milankovitch is wrong........................................................................................................................................96 1AR- Emilani is wrong ...............................................................................................................................................98 1AR- Ext. Warming caused past IA..............................................................................................................................99 1AR- Ext: High Risk of NAC failure..........................................................................................................................100

Gonzaga Debate Institute 2008

3 Ice Age

Scholars

Shell ( ) Greenhouse gas emissions are currently preventing an ice age Marsh 8 (Gerald, retired physicist from the Argonne National Laboratory and a former consultant to the Department of Defense on strategic nuclear technology and policy, The Coming of a New Ice Age; canadafreepress.com) There were very few Ice Ages until about 2.75 million years ago when Earth’s climate entered an unusual period of instability. Starting about a million years ago cycles of ice ages lasting about 100,000 years, separated by relatively short interglacial perioods, like the one we are now living in became the rule. Before the onset of the Ice Ages, and for most of the Earth’s history, it was far warmer than it is today. Indeed, the Sun has been getting brighter over the whole history of the Earth and large land plants have flourished. Both of these had the effect of dropping carbon dioxide concentrations in the atmosphere to the lowest level in Earth’s long history. Five hundred million years ago, carbon dioxide concentrations were over 13 times current levels; and not until about 20 million years ago did carbon dioxide levels dropped to a little less than twice what they are today. It is possible that moderately increased carbon dioxide concentrations could extend the current interglacial period. But we have not reached the level required yet, nor do we know the optimum level to reach. So, rather than call for arbitrary limits on carbon dioxide emissions, perhaps the best thing the UN’s Intergovernmental Panel on Climate Change and the climatology community in general could do is spend their efforts on determining the optimal range of carbon dioxide needed to extend the current interglacial period indefinitely. NASA has predicted that the solar cycle peaking in 2022 could be one of the weakest in centuries and should cause a very significant cooling of Earth’s climate. Will this be the trigger that initiates a new Ice Age? We ought to carefully consider this possibility before we wipe out our current prosperity by spending trillions of dollars to combat a perceived global warming threat that may well prove to be only a will-o-the-wisp.

( ) An ice age would cause extinction Pearson 8 (Christopher; Writer for the Weekend Australian; All-round Country Edition; A Cool Idea to Warm To; Lexis) A little ice age would be ``much more harmful than anything warming may do'', but still benign by comparison with the severe glaciation that for the past several million years has almost always blighted theplanet. The Holocene, the warm interglacial period we've been enjoying through the past 11,000 years, has lasted longer than normal and is due to come to an end. When it does, glaciation can occur quite quickly. For most of Europe and North America to be buried under a layer of ice, eventually growing to a thickness of about 1.5km, the required decline in global temperature is about 12C and it can happen in as little as 20 years. Chapman says: ``The next descent into an ice age is inevitable but may not happen for another 1000 years. On the other hand, it must be noted that the cooling in 2007 was even faster than in typical glacial transitions. If it continued for 20 years, the temperature would be 14C cooler in 2027. By then, most of the advanced nations would have ceased to exist, vanishing under the ice, and the rest of the world would be faced with a catastrophe beyond imagining. Australia may escape total annihilation but would surely be overrun by millions of refugees.'' Chapman canvases strategies that may just conceivably prevent or at least delay the transition to severe glaciation. One involves a vast bulldozing program to dirty and darken the snowfields in Canada and Siberia, ``in the hope of reducing reflectance so as to absorb more warmth from the sun. We may also be able to release enormous floods of methane (a potent greenhouse gas) from the hydrates under the Arctic permafrost and on the continental shelves, perhaps using nuclear weapons to destabilise the deposits''. He concludes: ``All those urging action to curb global warming need to take off the blinkers and give some thought to what we should do if we are facing global cooling instead. It will be difficult for people to face the truth when their reputations, careers, government grants or hopes for social change depend on global warming, but the fate of civilisation may be at stake.''

Gonzaga Debate Institute 2008 Scholars

**********Uniqueness/Link**********

4 Ice Age

Gonzaga Debate Institute 2008 Scholars

5 Ice Age

Uniqueness - IA Approaching ( ) An ice age is coming- glacial studies prove. Boyd in 5 (Elijah, Reporter for Science and Technology, ICE AGE - INTERVIEW WITH A GEOLOGIST, co2science.org) Global cooling Q: What evidence do you have of the Earth entering a new ice age? A: I have indeed been working on more information, and I have more hard temperature data coming from many places in the world [and] the activity of glaciers that are growing in many different places, such as Greenland, Norway, and Sweden. The Bering Glacier, the largest maritime glacier in Alaska, has advanced even more than I documented previously. It has gone down the valley 9 kilometers in the last 17 months, putting icebergs down the river that goes into Prince William Sound. The U.S. Geological Survey (USGS) has had to keep their eye on that because of all the oil tankers that come down there. The last data I have are for 1995. This is a rapidly growing glacier that covers 1,000 square miles and accumulates a lot, and now it is funnelling this accumulation down towards the ocean. There are now USGS professional papers, which are satellite atlases of the principal glacial areas of the world. Q- Are they on the web somewhere? A: The world glacier monitoring service is on the web. I have some copies of graphs from this coming to me, of many different glaciers which are surging, in many places in the world. But a lot of data about different glaciers are not on the web. Dr. Anker Wedek of the Geological Service of Denmark and Greenland, working with the USGS, has put together an atlas on Greenland, of which I just received a copy. It was done in 1995, and it reports on the large number of glaciers which are surging and increasing in volume in Greenland. The same thing is happening in Antarctica, with an even bigger glacier... Q: Is that the one that is adding 200 gigatons of ice per year? A: Yes, that was the estimate, done separately by different people. Professor Bentley, who did that work in Antarctica, was the principal author. His summary appeared in a 1993 issue of [the American Geophysical Union's magazine] Eos, along with some other rather complete papers. They said that that glacier in Antarctica is indeed increasing at 200 gigatons a year. It is also increasing in elevation at about 4 feet a year. This was measured by looking at some big ITT transmission towers, which are now way down in a hole (!). And, as the glacier adds about 4 feet of ice per year it doesn't stand still-it starts moving out. Therefore, although it's adding 4 feet a year of ice, it's only increasing in elevation at about, actually, two-tenths of a meter a year, because of the mass outflowage.

Gonzaga Debate Institute 2008 Scholars

6 Ice Age

Ext: GW  No Ice Age ( ) An increase in CO2 emissions prevents the next ice age. Tyrell in 6 (Writer for Science Daily; Next Ice Age Delayed By Rising Carbon Dioxide Levels; http://www.sciencedaily.com) Our research shows why atmospheric CO2 will not return to pre-industrial levels after we stop burning fossil fuels. It shows that it if we use up all known fossil fuels it doesn't matter at what rate we burn them. The result would be the same if we burned them at present rates or at more moderate rates; we would still get the same eventual ice-age-prevention result.' Ice ages occur around every 100,000 years as the pattern of Earth's orbit alters over time. Changes in the way the sun strikes the Earth allows for the growth of ice caps, plunging the Earth into an ice age. But it is not only variations in received sunlight that determine the descent into an ice age; levels of atmospheric CO2 are also important. Humanity has to date burnt about 300 Gt C of fossil fuels. This work suggests that even if only 1000 Gt C (gigatonnes of carbon) are eventually burnt (out of total reserves of about 4000 Gt C) then it is likely that the next ice age will be skipped. Burning all recoverable fossil fuels could lead to avoidance of the next five ice ages.

( ) Anthropogenic induced warming is the only factor that could offset the upcoming ice age. IDSO in 5 (Craig, Keith, Sherwood, CO2 Science Magazine, January 19, www.co2science.org) The authors contend that "ice-core evidence from previous interglaciations indicates that forcing by orbitalscale changes in solar radiation and greenhouse-gas concentrations should have driven earth's climate significantly toward glacial conditions during the last several thousand years," and that "the hypothesized reason most of this cooling did not occur is that humans intervened in the natural operation of the climate system by adding significant amounts of CO2 and CH4 to the atmosphere, thereby offsetting most of the natural cooling that otherwise would have occurred and fortuitously producing the climatic stability of the last several thousand years." If true, how did humans do it? Ruddiman et al. attribute the anomalous increase in atmospheric CO2 to massive early deforestation of Eurasia, while they link the anomalous CH4 increase to the introduction of irrigation for rice farming in southeast Asia, as well as to increases in biomass burning and the development of animal husbandry. What was done Based on the periodicities and phases of the natural cycles of CO2 and CH4 that are revealed in the 400,000-year Vostok ice core, Ruddiman et al. first determined that the air's CO2 concentration should have fallen to 240-245 ppm, whereas it gradually rose to a level of 280-285 ppm, just before the start of the Industrial Revolution, while the air's CH4 concentration rose to approximately 700 ppb when it should have fallen to about 450 ppb. Then, based on the IPCC sensitivity estimate of a 2.5 C temperature increase for a doubling of the air's CO2 content, they calculated that the supposedly anthropogenic-induced CO2 and CH4 anomalies should have produced an equilibrium warming of approximately 0.8 C on a global basis and 2 C in earth's polar regions. What was learned On the basis of these calculations, the authors conclude that "without any anthropogenic warming, earth's climate would no longer be in a full-interglacial state but well on its way toward the colder temperatures typical of glaciations," and that "an ice sheet would now be present in northeast Canada, had humans not interfered with the climate system." What it means If correct, the overdue-glaciation hypothesis indicates that in the absence of anthropogenic contributions of CO2 and CH4, the climate today would be, in the words of Ruddiman et al., "roughly one third of the way toward fullglacial temperatures," which also suggests that the extra CO2 we are currently releasing to the atmosphere via the burning of fossil fuels may well be what's keeping us from going the rest of the way. Hence, even if the IPCC is correct in their analysis of climate sensitivity and we are wrong in suggesting the sensitivity they calculate is way too large, the bottom line for the preservation of civilization and much of the biosphere is that governments ought not interfere with the normal progression of fossil fuel usage, for without more CO2 in the atmosphere, we could shortly resume the downward spiral to full-fledged ice-age conditions. Ought we not be doubly careful, therefore, as the United States indeed is, in not rushing forward to implement the Kyoto Protocol or anything like it? We certainly think so.

Gonzaga Debate Institute 2008 Scholars

7 Ice Age

Ext: GW  No Ice Age ( ) Decreasing greenhouse gas emissions will trigger an ice age Ruddiman 5 (William, et. Al, Department of Environmental Sciences at the University of Virginia, Quaternary Science) The relative temperature stability of the last 10,000 years has long been viewed as the result of natural climatic causes. Orbital variations are seen as having permitted a brief interglacial break between the previous glaciation and the next one, each encompassing 90% of the duration of a 100,000-year cycle. An accompanying view has persisted that humans played no significant role in altering atmospheric greenhousegas concentrations or affecting global climate until the 1800s, when byproducts of the industrial revolution begin to add measurably to the natural greenhouse-gas levels already in the atmosphere and to contribute to the warming trend of the last century (IPCC, 2001). Both of these concepts have been challenged (Ruddiman, 2003). Ice-core evidence from previous interglaciations indicates that forcing by orbital-scale changes in solar radiation and greenhouse-gas concentrations should have driven Earth’s climate significantly toward glacial conditions during the last several thousand years. The hypothesized reason that most of this cooling did not occur is that humans intervened in the natural operation of the climate system by adding significant amounts of CO2 and CH4 to the atmosphere, thereby offsetting most of the natural cooling and fortuitously producing the climatic stability of the last several thousand years. One prediction of this hypothesis is that early anthropogenic greenhouse-gas emissions stopped a glaciation that otherwise would have begun several millennia ago.

( ) AND, the reduction of CO2 via the aff plan will cause another ice age. McMillan 2 (Bruce McMillan, Director of Illinois State Museum, http://www.museum.state.il.us/exhibits/ice_ages) A general reduction in the amount of carbon dioxide (CO2) in the atmosphere may contribute to the development of ice ages. Carbon dioxide is an important greenhouse gas. Decreases in the amount of CO2 in the atmosphere may lead to global cooling. Many processes can cause a long-term decrease in the amount of CO2 in the atmosphere. These processes include many complex interactions among organisms, ocean currents, erosion, and volcanism. Important relationships exist between ice ages and the composition of the atmosphere; however, many scientists are unsure whether the changes in atmosphere cause cool periods or whether cool periods cause atmospheric changes. Also, many scientists are not sure the magnitude of past CO2 changes was large enough to initiate ice ages.

( ) CO2 emissions will actually allow us to skip the next ice age. Flam 2 (Faye, Inquirer Staff Writer for the Philadelphia Inquirer,; Global Warming Might Stall the Next Ice Age; Lexis) Though there are some dissenters, many climate experts estimate the global temperature will rise between 4 and 9 degrees by the end of the 21st century. "The warming will certainly launch us into a new interval in terms of climate, far outside what we've seen before," said Crowley. In the long run, he said, carbon dioxide emissions could cause the cycle of ice ages to "skip a beat." Loutre and Berger estimated that human activity would double the concentration of carbon dioxide in the atmosphere over the next two centuries. Still, "it could get much worse," said Crowley. There's a huge reservoir of coal and if people keep burning it, they could more than quadruple the present carbon dioxide concentrations, he said.

Gonzaga Debate Institute 2008 Scholars

8 Ice Age

Ext: GW  No Ice Age ( ) Global warming is the only way to delay the ice age. We control timeframe on this question. Flam in 2 (Faye, Inquirer Staff Writer for the Philadelphia Inquirer,; Global Warming Might Stall the Next Ice Age; Lexis) It may be hot now, but it's never too early to start thinking about the next ice age. Based on the Earth's historical cycle of warm and cold periods, we're due for a big freeze any millennium now. If the next cold spell is like the last one, which ended 10,000 years ago, glaciers would cover much of North America, creeping as far south as New York City. Ice ages and warmer "interglacials" alternate in cycles. In the last few cycles, the relatively warm "interglacials" lasted about 10,000 years. Since our current interglacial started about 10,000 years ago, it's due to end any time now. The cold periods last much longer than the warm ones - 80,000 to 100,000 years. Over the whole planet, ice ages reduce temperatures by only about 10 degrees, but the chill is more pronounced in temperate zones - such as most of the United States. "If you were living in Philadelphia, you could have taken a day trip to see the ice sheet," said Duke University climatologist Tom Crowley. A 50-foot-thick glacier covered Long Island back then, he said. But there's the possibility that ongoing global warming could delay the onset of the next big freeze by thousands of years, according to Belgian researchers, writing in today's issue of the journal Science. "We've shown that the input of greenhouse gas could have an impact on the climate 50,000 years in the future," said Marie-France Loutre of the Universite Catholique de Louvain in Belgium. Factoring in the higher concentration of carbon dioxide in the atmosphere, Loutre and colleague Andre Berger found that the next ice age may not come for a few more tens of thousands of years. The increase in carbon dioxide, many scientists believe, has come primarily from the increased burning of fossil fuels, such as coal, oil and gas. Scientists don't normally connect global warming with ice ages since they happen on very different time scales decades for global warming, compared with tens of thousands of years for ice ages, said Princeton climatologist Jorge Sarmiento. Still, he said, "it's not an unreasonable idea... . It's something I've contemplated." His own work, he said, has backed Loutre's contention that today's increased carbon dioxide should linger for millennia - long enough to influence the far-future forecast. Some of the extra carbon dioxide will be eventually dissolved in the oceans, he said, "but that takes a long time." This summer not withstanding, we're in a relatively cold period compared with most of the planet's history. When dinosaurs roamed New Jersey, 100 million years ago, it was about 15 degrees warmer than today, with little permanent ice anywhere. But it's considerably warmer now than during the last ice age.

( ) CO2 emissions will allow us to skip the next ice age. Flam in 2 (Faye, Inquirer Staff Writer for the Philadelphia Inquirer,; Global Warming Might Stall the Next Ice Age; Lexis) Though there are some dissenters, many climate experts estimate the global temperature will rise between 4 and 9 degrees by the end of the 21st century. "The warming will certainly launch us into a new interval in terms of climate, far outside what we've seen before," said Crowley. In the long run, he said, carbon dioxide emissions could cause the cycle of ice ages to "skip a beat." Loutre and Berger estimated that human activity would double the concentration of carbon dioxide in the atmosphere over the next two centuries. Still, "it could get much worse," said Crowley. There's a huge reservoir of coal and if people keep burning it, they could more than quadruple the present carbon dioxide concentrations, he said.

( ) Reduction of CO2 will cause another ice age. McMillan in 2 (Bruce McMillan, Director of Illinois State Museum, http://www.museum.state.il.us/exhibits/ice_ages) A general reduction in the amount of carbon dioxide (CO2) in the atmosphere may contribute to the development of ice ages. Carbon dioxide is an important greenhouse gas. Decreases in the amount of CO2 in the atmosphere may lead to global cooling. Many processes can cause a long-term decrease in the amount of CO2 in the atmosphere. These processes include many complex interactions among organisms, ocean currents, erosion, and volcanism. Important relationships exist between ice ages and the composition of the atmosphere; however, many scientists are unsure whether the changes in atmosphere cause cool periods or whether cool periods cause atmospheric changes. Also, many scientists are not sure the magnitude of past CO2 changes was large enough to initiate ice ages.

Gonzaga Debate Institute 2008 Scholars

9 Ice Age

Ext: GW  No Ice Age ( ) Human-induced warming prevents the catastrophic impacts of another ice age. An increase in emissions prevents home displacement, famine, and world chaos. We win. 1 Ray in 5 (John, (M.A.; Ph.D.), writing from Australia, Man-Made Global Warming Hoax http://antigreen.blogspot.com) Humans may have unwittingly saved themselves from a looming ice age by interfering with the Earth's climate, according to a new study. The findings from a team of American climate experts suggest that were it not for greenhouse gases produced by humans, the world would be well on the way to a frozen Armageddon. Scientists have traditionally viewed the relative stability of the Earth's climate since the end of the last ice age 10,000 years ago as being due to natural causes. But there is evidence that changes in solar radiation and greenhouse gas concentrations should have driven the Earth towards glacial conditions over the last few thousand years. What stopped it has been the activity of humans, both ancient and modern, argue the scientists. Over the last 8,000 years carbon dioxide levels in the atmosphere have gradually risen, when previous trends indicated that it should have dropped. Methane, another greenhouse gas, had also increased instead of fallen. The unexpected trends could be explained by massive early deforestation in Eurasia, rice farming in Asia, the introduction of livestock, and the burning of wood and plant material, all of which led to an outpouring of greenhouse emissions. The United States researchers, led by William Ruddiman from the University of Virginia in Charlottesville, used a climate model to test what would happen if these greenhouse gases were reduced to their "natural" level. They wrote in the journal Quaternary Science Reviews: "In the absence of anthropogenic contributions, global climate is almost 2C cooler than today and roughly one third of the way toward full glacial temperatures." At the peak of the last ice age, which began 70,000 years ago, 97% of Canada was covered by ice. The research showed that without the human contribution to global warming, Baffin Island would today be in a condition of "incipient glaciation". "Portions of Labrador and Hudson Bay would also have moved very close to such a state had greenhouse gas concentrations followed natural trends," said the scientists. The experiment had probably underestimated the amount of ice that would exist today in north-east Canada without human interference, they said. The number of potential influences on the model was deliberately limited in order to highlight the effect of greenhouse gases. It did not take into account the effect of increased ice cover, which would have caused further cooling by reflecting back the sun's rays. Dynamic ocean processes were also not accounted for. Anthropologist Dr Benny Peiser, from Liverpool John Moores University, said: "If the research findings are correct, a radical change in the perception of anthropogenic greenhouse gas emissions will be required. "Instead of driving us to the brink of environmental disaster, human intervention and technology progress will be seen as vital activities that have unintentionally delayed the onset of a catastrophic ice age."

( ) Warming has caused climactic stability and it has offset the next ice age. Ruddiman in 5 (William, et. Al, Department of Environmental Sciences at the University of Virginia, Quaternary Science) The relative temperature stability of the last 10,000 years has long been viewed as the result of natural climatic causes. Orbital variations are seen as having permitted a brief interglacial break between the previous glaciation and the next one, each encompassing 90% of the duration of a 100,000-year cycle. An accompanying view has persisted that humans played no significant role in altering atmospheric greenhousegas concentrations or affecting global climate until the 1800s, when byproducts of the industrial revolution begin to add measurably to the natural greenhouse-gas levels already in the atmosphere and to contribute to the warming trend of the last century (IPCC, 2001). Both of these concepts have been challenged (Ruddiman, 2003). Ice-core evidence from previous interglaciations indicates that forcing by orbital-scale changes in solar radiation and greenhouse-gas concentrations should have driven Earth’s climate significantly toward glacial conditions during the last several thousand years. The hypothesized reason that most of this cooling did not occur is that humans intervened in the natural operation of the climate system by adding significant amounts of CO2 and CH4 to the atmosphere, thereby offsetting most of the natural cooling and fortuitously producing the climatic stability of the last several thousand years. One prediction of this hypothesis is that early anthropogenic greenhouse-gas emissions stopped a glaciation that otherwise would have begun several millennia ago.

Gonzaga Debate Institute 2008 Scholars

10 Ice Age

Ext: GW  No Ice Age ( ) Our modern emissions habits are examples of technological manipulation of our environment. Without interference our earth would be covered in ice, this outweighs any warming impacts. Telegraph in 5 SUNDAY TELEGRAPH 1-30-05 For some reason, environmentalists seem convinced that anything mankind does must be worse than leaving Mother Nature to her own devices. In reality, Mother Nature has been trying to plunge us back into an ice age for thousands of years. For the whole of recorded history, we have been living in an unusual "interglacial" period - and we should be mighty glad that it shows no signs of closing. Indeed, the real question is why it has remained open so long. The ebb and flow of ice ages are controlled by astronomical cycles in the orbit and orientation of the Earth in space, and calculations suggest that the interglacial window should have begun closing since Biblical times. In a paper just published in the journal Quaternary Science Reviews, a team of climate scientists led by Prof William Ruddiman of the University of Virginia puts forward one explanation - but you just know that eco-warriors are going to hate it. The team suggests that the ice age has been fended off because mankind has been "interfering" with Mother Nature for far longer than we think. The current flap over global warming focuses on the past 150 years or so, when fossil fuel burning and population growth really started to take off. Yet the resulting global warming should have been just a blip on a downward trend in temperature presaging the return of the ice age. Prof Ruddiman and his colleagues have taken a much longer view, and looked at ways that mankind could have affected the Earth climate since the dawn of history.In their paper, they argue that a combination of ancient agriculture, deforestation and biomass burning can boost the key "greenhouse gases" carbon dioxide and methane to levels cancelling out the cooling that should have occurred over the past few thousand years.To get some idea of what might otherwise have happened, the team studied geological records from around 400,000 years ago, when the ice age was at the same part of its cycle as it is today. The results are sobering. With no means of influencing the climate, prehistoric humans would have found themselves besieged by giant ice-sheets and bitterly cold conditions. Modelling by the team showed annual average temperatures dropping by 5.5°F over North America and Northwest Europe and winter temperatures plunging by 8°F.

( ) Human CO2 emissions are staving off the next ice age. Ruddiman in 5 (William, et. Al, Department of Environmental Sciences at the University of Virginia, Quaternary Science) The 2 1C mean-annual cooling simulated by removing anthropogenic greeenhouse gases (Fig. 3a) is equivalent to roughly one third of the global-mean difference between full-interglacial and full-glacial climates (CLIMAP, 1981; Mix et al., 2001). It also represents 80% of the warming simulated by the GENESIS 2 model in response to a doubling of modern CO2 (Thompson and Pollard, 1997). Without any anthropogenic warming, Earth’s climate would no longer be in a full-interglacial state but well on its way toward the colder temperatures typical of glaciations.

( ) We’re headed for cooling now- warming solves. Bischof 02 (Jens Bischof is author of Ice Drift, Ocean Circulation And Climate Change and is a research assistant professor in Old Dominion’s Department of Ocean, Earth and Atmospheric Sciences. “Ice In The Greenhouse:Earth May Be Cooling, Not Warming” from Quest January 2002 • Volume 5 Issue 1 http://www.odu.edu/ao/instadv/quest/greenhouse.html accessed June 29, 2008) In the meantime, we should prepare ourselves for the possibility that our cherished ideas about global warming may be, if not dead wrong, only partially correct. Intriguing recent evidence gathered from icerafted debris looks remarkably similar to a much older pattern that preceded an ice age. We may have to entertain the possibility that Earth’s natural climate development may be on a return to another such period, or at least to colder conditions than we now experience. If so, and ironically, the very greenhouse warming we fear may either mitigate the cooling or cancel it altogether.

Gonzaga Debate Institute 2008 Scholars

11 Ice Age

Increased Warming Key ( ) Scientists and think tanks alike both believe that warming needs to accelerate to offset the upcoming ice age. Joyce and Keigwin in 8 (Terrence, Senior Scientist, Physical Oceanography and Lloyd, Senior Scientist, Geology & Geophysics; Are We on the Brink of a 'New Little Ice Age?; May 7) Indeed, some groups advocate the benefits of global warming, including the Greening Earth Society and the Subtropical Russia Movement. Some in the latter group even advocate active intervention to accelerate the process, seeing this as an opportunity to turn much of cold, austere northern Russia into a subtropical paradise. Evidence has mounted that global warming began in the last century and that humans may be in part responsible. Both the Intergovernmental Panel on Climate Change (IPCC) and the US National Academy of Sciences concur. Computer models are being used to predict climate change under different scenarios of greenhouse forcing and the Kyoto Protocol advocates active measures to reduce CO² emissions which contribute to warming. Thinking is centered around slow changes to our climate and how they will affect humans and the habitability of our planet. Yet this thinking is flawed: It ignores the well-established fact that Earth’s climate has changed rapidly in the past and could change rapidly in the future. The issue centers around the paradox that global warming could instigate a new Little Ice Age in the northern hemisphere. Evidence for abrupt climate change is readily apparent in ice cores taken from Greenland and Antarctica. One sees clear indications of long-term changes discussed above, with CO² and proxy temperature changes associated with the last ice age and its transition into our present interglacial period of warmth. But, in addition, there is a strong chaotic variation of properties with a quasiperiod of around 1500 years. We say chaotic because these millennial shifts look like anything but regular oscillations. Rather, they look like rapid, decade-long transitions between cold and warm climates followed by long interludes in one of the two states.

( ) Cooling has an exponential effect on our earth. An increase in snow and ice reflects 80% of incoming radiant energy. This significant loss of potential heat calls for an acceleration of warming, Tkachuck in 5 (Richard; Geoscience Research Institute; November; The Little Ice Age; http://www.grisda.org) After the cooling event has begun, it can, to some extent, become self-perpetuating. With increased snow cover the amount of energy absorbed by the earth is reduced. Up to 80% of the incoming radiant energy normally captured can be lost due to the reflectivity of the snow and ice (Lamb 1977, p. 285). This is a significant loss of potential heat, further exacerbating the cooling effect. The polar latitudes are a constant area of heat loss for the global system. In summer the amount of heat absorbed is not equal to the amount lost during the winter. Were it not for an equal overbalance in the equatorial regions where heat gain is 2.5 times greater than heat loss, the Earth would become increasingly colder. The mixing of the excess equatorial heat with the overall heat deficit in the northern latitudes promotes a stable environment that can be maintained even in latitudes where there is net heat loss, e.g., the temperate zones.The presence of large bodies of water such as oceans tends to balance the cooling trend on the land masses. As the air and water temperatures cool, less moisture is evaporated into the atmosphere resulting in less rain or snow. If precipitation is less, a relative increased melting of previously fallen snow can take place.

Gonzaga Debate Institute 2008 Scholars

**********IA Impacts**********

12 Ice Age

Gonzaga Debate Institute 2008 Scholars

13 Ice Age

IA Impacts - General ( ) A new ice age is due now and its impacts are catastrophic. Famine, world chaos, and world war win timeframe and magnitude against global warming. Kenny in 2 (Andrew Kenny, Sunday Mail for Queensland, Australia; FEATURES; Pg. 54; July 14, 2002, Sunday; Lexis Nexis) A new ice age is due now, says ANDREW KENNY, but you won't hear it from green groups, who like to play on Western guilt about consumerism to make us believe in global warming THE Earth's climate is changing in a dramatic way, with immense danger for mankind and the natural systems that sustain it. This was the frightening message broadcast to us by environmentalists in the recent past. Here are some of their prophecies. The facts have emerged, in recent years and months, from research into past ice ages. They imply that the threat of a new ice age must now stand alongside nuclear war as a likely source

of wholesale death and misery for mankind. The cooling has already killed thousands of people in poor nations . . . If it continues, and no strong measures are taken to deal with it, the cooling will cause world famine, world chaos, and probably world war, and this could all come about by the year 2000. As recently as January 1994, the supreme authority on matters environmental, Time magazine, wrote: The ice age cometh? Last week's big chill was a reminder that the Earth's climate can change at any time . . . The last (ice age) ended 10,000 years ago; the next one -- for there will be a next

one -- could start tens of thousands of years from now. Or tens of years. Or it may have already started. The scare about global cooling was always the same: unprecedented low temperatures; the coldest weather recorded; unusual floods and storms; a rapid shift in the world's climate towards an icy apocalypse. But now, the scare is about global warming. To convert from the first scare to the second, all you have to do is substitute "the coldest weather recorded" with "the warmest weather recorded". Replace the icicles hanging from oranges in California with melting glaciers on Mt Everest, and the shivering armadillos with sweltering polar bears. We were going to freeze but now we are going to fry. Even the White House is making cautionary sounds about warming. What facts have emerged to make this dramatic reversal? Well, none really. The most reliable measurements show no change whatsoever in global temperatures in the past 20 years. What has changed is the perception that global warming makes a better scare than the coming ice age. A good environmental scare needs two ingredients. The first is impending catastrophe. The second is a suitable culprit to blame. In the second case, the ice age fails and global warming is gloriously successful.

Gonzaga Debate Institute 2008 Scholars

14 Ice Age

IA Impacts - General ( ) We control empirics on this question; evidence shows that a past cooling caused widespread drought and famine that reduced human pop. to 15000. A sizeable ice age spells extinction. Whitehouse in 98 (Dr David, BBC News Online science editor; Humans came 'close to extinction'; http://news.bbc.co.uk) A new hypothesis about recent human evolution suggests that we came very close to extinction because of a "volcanic winter" that occurred 71,000 years ago. Some scientists estimate that there may have been as few as 15,000 humans alive at one time. The volcanic winter lasted about six years. It was followed by 1,000 years of the coldest Ice Age on record. It brought widespread famine and death to human populations around the world. It also affected subsequent human evolution. This was because of a so-called bottleneck effect. The rapid decrease, in our ancestors' populations, in turn, brought about the rapid differentiation - or genetic divergence - of the surviving populations. The idea is being advocated by Professor Stanley Ambrose of the University of Illinois. He believes that the eruption of Mount Toba in Sumatra caused the bottleneck. "Modern human races may have diverged abruptly, only 70,000 years ago," he writes in the Journal of Human Evolution. Geneticists have thought for some time that humans passed through a recent evolutionary bottleneck but they had little idea what may have caused it. Scientists believe that an eruption of Toba caused a volcanic winter that lasted six years and significantly altered global climate for the next 1,000 years. During those six years, there was substantial lowering of global temperatures, drought and famine. No more than 15,000 people survived. When better conditions returned, the human population was able to grow once more and develop the genetic diversity we see today. "When our African recent ancestors passed through the prism of Toba's volcanic winter, a rainbow of differences appeared," Professor Ambrose said.

( ) An ice age could lead to crop failure, drought, famine, plague, and war. Gunter in 8 (Lorne,Canadian Centre for Libertarian Studies; Welcome to the new ice age; nationalpost.com) He is not alone. Kenneth Tapping of our own National Research Council, who oversees a giant radio telescope focused on the sun, is convinced we are in for a long period of severely cold weather if sunspot activity does not pick up soon. The last time the sun was this inactive, Earth suffered the Little Ice Age that lasted about five centuries and ended in 1850. Crops failed through killer frosts and drought. Famine, plague and war were widespread. Harbours froze, so did rivers, and trade ceased.

Gonzaga Debate Institute 2008 Scholars

15 Ice Age

IA Impacts – Species Extinction ( ) An ice age would destroy entire species. 2/3 of all the species on the planet were destroyed by the last ice age. CNN in 4 (CNN, Science & Space, Supernova, sun combo blamed for mass extinction; http://www.cnn.com/2004/TECH) "The prevailing theory for that extinction has been an ice age," said Adrian L. Melott, a University of Kansas astronomer. "We think there is very good circumstantial evidence for a gamma ray burst." Melott is the leader of a team, which includes some astronomers from the National Aeronautics and Space Administration, that presented the theory Wednesday at the national meeting of the American Astronomical Society. Fossil records for the Ordovician extinction show an abrupt disappearance of two-thirds of all species on the planet. Those records also show that an ice age that lasted more than a half million years started during the same period. Melott said a gamma ray burst would explain both phenomena. He said a gamma ray beam striking the Earth would break up molecules in the stratosphere, causing the formation of nitrous oxide and other chemicals that would destroy the ozone layer and shroud the planet in a brown smog. "The sky would get brown, but there would be intense ultraviolet radiation from the sun striking the surface." he said. The radiation would be at least 50 times above normal, powerful enough to killed exposed life. In a second effect, the brown smog would cause the Earth to cool, triggering an ice age, Melott said. The extinction "could have been a one-two punch," said Bruce S. Lieberman, a paleontologist at the University of Kansas and a co-author of the theory. "Our theory builds on earlier theories" that included an ice age. Before the extinction, the Earth was unusually warm. Melott said climate experts have been unable to find a model that would explain the sudden onset of massive glaciers. "They need something to jump start the ice age," he said. "The gamma ray burst could have done it."

Gonzaga Debate Institute 2008 Scholars

16 Ice Age

IA Impacts- Species Extinction ( ) Extensive research and experimentation proves that an ice age would destroy our ecosystem and extinguish many species of mammals. Boyd in 5 (Elijah, Reporter for Science and Technology, ICE AGE - INTERVIEW WITH A GEOLOGIST, co2science.org) Global cooling Q: Well, what are the consequences if the temperature is falling? A: There are many plants and animals that will no longer be able to survive in the northern most areas. There was a paper published in Nature in 1993, which analyzed the pollen in southern Ontario, south of Lake Nipigon, in the last 650 years. The forest there used to be a temperate forest, beech and maples. The maples died out and gave way to oaks, then the oaks died out, and gave way to white pines. Now the white pines are disappearing and being displaced southward, and all that's coming back is boreal forest, not a temperate forest. The boreal forest is of birches and aspen. Those are characteristic of what grows way up north in Scandinavia. So, in the last 650 years, southern Ontario has gone into the boreal plant zone. For them, the Holocene [the most recent geological epoch] is over! They can probably expect some global warming in about 100,000 years, after the ice melts that's going to cover Canada. This is the meaning of this good pollinology study. Now, such a change happened before, in southeastern France, in the last interglacial period, the Eemian, 115,000 years ago. This was also published in Nature, by Voillard. They had a temperate forest of hardwoods. Then, in the space of about 20 years-that's a pretty short time-frame-a rapid cooling took place that killed off the temperate forests. All the hardwoods died, and all that was left was boreal forest, the pine, birch, and spruce. The boreal plant zone, which is today about at the level of Helsinki, Finland, was displaced southward to the Vosges Mountains, in France, From 60 degrees north latitude, to 47 degrees north latitude, This happened in 20 years! Now, that would be like taking the current boreal plant zone on the north side of Lake Superior, and displacing it south to Georgia, in 20 years. That's going to happen. It'll be just like the area moved to Scandinavia.

Gonzaga Debate Institute 2008 Scholars

17 Ice Age

IA Impacts – Disease ( ) Previous ice ages prove that diseases would run rampant. With convulsions, hallucinations, and gangerous rotting, living through these could be worse than death. Mandia in 7 (Scott A.; Professor of Physical Sciences @ SCCC.; The Little Ice Age in Europe; www2.sunysuffolk.edu) The cooler climate during the LIA had a huge impact on the health of Europeans. As mentioned earlier, dearth and famine killed millions and poor nutrition decreased the stature of the Vikings in Greenland and Iceland. Cool, wet summers led to outbreaks of an illness called St. Anthony's Fire. Whole villages would suffer convulsions, hallucinations, gangrenous rotting of the extremities, and even death. Grain, if stored in cool, damp conditions, may develop a fungus known as ergot blight and also may ferment just enough to produce a drug similar to LSD. (In fact, some historians claim that the Salem, Massachusetts witch hysteria was the result of ergot blight.) Malnutrition led to a weakened immunity to a variety of illnesses. In England, malnutrition aggravated an influenza epidemic of 1557-8 in which whole families died. In fact, during most of the 1550's deaths outnumbered births (Lamb, 1995.) The Black Death (Bubonic Plague) was hastened by malnutrition all over Europe.

Gonzaga Debate Institute 2008 Scholars

18 Ice Age

IA Impacts – War ( ) An ice age would incite mass migrations that’d culminate in violence. As a deterrence some countries would declare wars; and others would run scarce of resources because of overpopulation. Bingel in 7 (Dr. Ferit, Middle East Technical University of Marine Sciences, May 25 Ice Age Possible for Scandinavia?; behav.org) Within recent months, the Pentagon has released a study about the climate changing and the effect it would have on the world. An abrupt temperature change would come eventually and it would be inevitable. The study was based on information from 8200 years ago when the earth went through the same change. A sudden cooling of the earth appeared after a long, extended heat wave. At this time, the Gulf Stream collapsed. Because of this past data, the study suggests the fate of Europe. Although there is no way to make sure that the information can be used to foresee what will happen to the present day, the study does suggest some startling possibilities. The collapse of the Stream would be more visible in northern Europe for the first five years. The annual rainfall would decrease by 30%, causing a severe drought. An increase in wind would cause the temperature to drop about six degrees. Snow would remain on the ground, making Scandinavia in a constant winter phase. The cold would stretch onto the latter months making the summer cooler then before. Humans could neither develop agriculture or permanant settlements and in turn would move southward onto other parts of Europe, being pushed by the colder, unstable temperature from home. As the population moves, fights and even battles would break out within the mass migration. Resources within other countries would decline because of the sudden increase in population within their own country. In defense, some countries would declare war. Not only would a climatic change move the population, but the fish, wildlife, water and energy consumption all would be effected. By the end of the decade, Europe's weather would be more of a mirror image of Siberia's or northern Canada's then what it looked like in the past. Unfortunately, the duration of this process could take decades and even centuries.

Gonzaga Debate Institute 2008 Scholars

19 Ice Age

IA Impacts – Famine ( ) A micro-ice age that Europe endured caused the agricultural yield to be reduced by up to 20% causing mass famines and millions of deaths. Mandia in 7 (Scott A.; Professor of Physical Sciences @ SCCC.; The Little Ice Age in Europe; www2.sunysuffolk.edu) Lamb (1966) points out that in the warmest times of the last 1000 years, southern England had the climate that northern France has now. For example, the difference between the northen-most vineyard in England in the past and present-day vineyard locations in France is about 350 miles. In other terms that means the growing season changed by 15 to 20 percent between the warmest and coldest times of the millenium. That is enough to affect almost any type of food production, especially crops highly adapted to use the full-season warm climatic periods. During the coldest times of the LIA, England's growing season was shortened by one to two months compared to present day values. The availability of varieties of seed today that can withstand extreme cold or warmth, wetness or dryness, was not available in the past. Therefore, climate changes had a much greater impact on agricultural output in the past. Each of the peaks in prices corresponds to a particularly poor harvest, mostly due to unfavorable climates with the most notable peak in the year 1816 - "the year without a summer." One of the worst famines in the seventeenth century occurred in France due to the failed harvest of 1693. Millions of people in France and surrounding countries were killed. The effect of the LIA on Swiss farms was also severe. Due to the cooler climate, snow covered the ground deep into spring. A parasite, known as Fusarium nivale, which thrives under snow cover, devastated crops. Additionally, due to the increased number of days of snow cover, the stocks of hay for the animals ran out so livestock were fed on straw and pine branches. Many cows had to be slaughtered. In Norway, many farms located at higher latitudes were abandoned for better land in the valleys. By 1387, production and tax yields were between 12 percent and 70 percent of what they had been around 1300. In the 1460's it was being recognized that this change was permanent. As late as the year 1665, the total Norwegian grain harvest is reported to have been only 67 - 70 percent of what it had been about the year 1300 (Lamb, 1995.)

Gonzaga Debate Institute 2008 Scholars

20 Ice Age

IA Impacts – Economy ( ) Even the risk of a slight cooling period is enough to throw our economy into a recession. When conditions get cooler, past examples prove the economy has slowed down. Engdahl in 8 (F. William; Writer for Centre of Research on Globalization; Global Warming gets the Cold Freeze; April 9) There have been so many snow and ice storms in Ontario and Quebec in the past two months that the real estate market has been hurt as home buyers have stayed home. In just the first two weeks of February, Toronto received 70 cm of snow, breaking the record of 66.6 cm for the entire month set back in 1950. One of the most dramatic results of the record cold over much of the planet is the reversal of the much-reported melt of the icebergs in the Arctic Ocean. Last autumn the world was alarmed to hear from certain climatologists that the ice in the Arctic had melted to its "lowest levels on record.” What was carefully omitted from those scare stories was the fact that those records only date back as far as 1972, and that there is anthropological and geological evidence of much greater melts in the past.Now, as a result of the recent record cold weather, the ice is back. According to Gilles Langis, a senior forecaster with the Canadian Ice Service in Ottawa, the Arctic winter has been so severe the ice has not only recovered, it is actually 10 to 20 cm thicker in many places than at this time last year.What few people know and what the Global Warming lobby seems at pains to keep known is the fact that there is considerable seasonal variation in how much pack ice of the Arctic ice pack covers the Arctic Ocean. Much of the ocean is also covered in snow for about 10 months of the year. The maximum snow cover is in March or April — about 20 to 50 centimeters over the frozen ocean. The thickness is not one of the universal constants, never was.

( ) An ice age would destroy the economy. The market of crops would quickly become inflated and many economies would lose tax revenues creating a domino-collapse effect. Mandia in 7 (Scott A.; Professor of Physical Sciences @ SCCC.; The Little Ice Age in Europe; www2.sunysuffolk.edu) In addition to increasing grain prices and lower wine production, there were many examples of economic impact by the dramatic cooling of the climate. Due to famine, storms, and growth of glaciers ,many farmsteads were destroyed, which resulted in less tax revenues collected due to decreased value of the properties (Lamb, 1995.) Cod fishing greatly decreased, especially for the Scottish fisherman, as the cod moved farther south. The cod fishery at the Faeroe Islands began to fail around 1615 and failed altogether for thirty years between 1675 and 1704 (Lamb, 1995.) In the Hohe Tauern mountains of the Austrian Alps, advancing glaciers closed the gold mines of the Archbishop of Salzburg who was one of the wealthiest dukes in the empire. The succession of two or three bad summers where the miners could not rely on work in the mines caused them to find employment elsewhere, which resulted in an abrupt end to the mining operations (Bryson, 1977.)

Gonzaga Debate Institute 2008 Scholars

21 Ice Age

IA Impacts – Refugees ( ) An ice would cause mass migrations and result in ultimate violence. Bingel in 7 (Dr. Ferit, Middle East Technical University of Marine Sciences, May 25 Ice Age Possible for Scandinavia?; behav.org) Within recent months, the Pentagon has released a study about the climate changing and the effect it would have on the world. An abrupt temperature change would come eventually and it would be inevitable. The study was based on information from 8200 years ago when the earth went through the same change. A sudden cooling of the earth appeared after a long, extended heat wave. At this time, the Gulf Stream collapsed. Because of this past data, the study suggests the fate of Europe. Although there is no way to make sure that the information can be used to foresee what will happen to the present day, the study does suggest some startling possibilities. The collapse of the Stream would be more visible in northern Europe for the first five years. The annual rainfall would decrease by 30%, causing a severe drought. An increase in wind would cause the temperature to drop about six degrees. Snow would remain on the ground, making Scandinavia in a constant winter phase. The cold would stretch onto the latter months making the summer cooler then before. Humans could neither develop agriculture or permanant settlements and in turn would move southward onto other parts of Europe, being pushed by the colder, unstable temperature from home. As the population moves, fights and even battles would break out within the mass migration. Resources within other countries would decline because of the sudden increase in population within their own country. In defense, some countries would declare war. Not only would a climatic change move the population, but the fish, wildlife, water and energy consumption all would be effected. By the end of the decade, Europe's weather would be more of a mirror image of Siberia's or northern Canada's then what it looked like in the past. Unfortunately, the duration of this process could take decades and even centuries.

Gonzaga Debate Institute 2008 Scholars

22 Ice Age

IA Impacts – Storms ( ) Ice Ages cause a high frequency of storms. The number of sea floods, hailstorms, and sandstorms could cause a multitude of damage. We control empirics on this question. Mandia in 7 (Scott A.; Professor of Physical Sciences @ SCCC.; The Little Ice Age in Europe; www2.sunysuffolk.edu) During the LIA, there was a high frequency of storms. As the cooler air began to move southward, the polar jet stream strengthened and followed, which directed a higher number of storms into the region. At least four sea floods of the Dutch and German coasts in the thirteenth century were reported to have caused the loss of around 100,000 lives. Sea level was likely increased by the long-term ice melt during the MWP which compounded the flooding. Storms that caused greater than 100,000 deaths were also reported in 1421, 1446, and 1570. Additionally, large hailstorms that wiped out farmland and killed great numbers of livestock occurred over much of Europe due to the very cold air aloft during the warmer months. Due to severe erosion of coastline and high winds, great sand storms developed which destroyed farmlands and reshaped coastal land regions. Impact of Glaciers During the post-MWP cooling of the climate, glaciers in many parts of Europe began to advance. Glaciers negatively influenced almost every aspect of life for those unfortunate enough to be living in their path. Glacial advances throughout Europe destroyed farmland and caused massive flooding. On many occasions bishops and priests were called to bless the fields and to pray that the ice stopped grinding forward (Bryson, 1977.) Various tax records show glaciers over the years destroying whole towns caught in their path. A few major advances, as noted by Ladurie (1971), appear below:

Gonzaga Debate Institute 2008 Scholars

***********Probability***********

23 Ice Age

Gonzaga Debate Institute 2008 Scholars

24 Ice Age

Present Temp Drop ( ) Empirical and present evidence proves that an ice age is upcoming. We control probability on this question. Pearson in 8 (Christopher; Writer for the Weekend Australian; All-round Country Edition; A Cool Idea to Warm To; Lexis) The 10-year plateau in global temperatures since 1998 has already sunk the hypothesis that anthropogenic greenhouse gas will lead to catastrophic global warming. To minds open to the evidence, it has been a collapsing paradigm for quite some time. But Chapman's argument about last year's 0.7C fall being ``the fastest temperature change in the instrumental record'' ups the stakes considerably. It replaces an irrational panic in the public imagination with a countervailing and more plausible cause for concern. It also raises, more pointedly than before, a fascinating question: since there are painful truths with profound implications for public policy to be confronted, how will the political class manage the necessary climb-down? In Australia, Rudd Labor's political legitimacy is inextricably linked to its stance on climate change. If the Prime Minister wants a second term, he'll probably have to start ``nuancing his position'', as the spin doctors say, and soon. A variation on J.M. Keynes's line -- ``when the facts change, I change my mind'' -- admitting that the science is far from settled and awaiting further advice, would buy him time without necessarily damaging his credibility. Taking an early stand in enlightening public opinion would be a more impressive act of leadership. While obviously not without risk and downside, it would make a virtue out of impending necessity and establish him, in Charles de Gaulle's phrase, as a serious man. I don't think he's got it in him. But we can at least expect that some of the more ruinously expensive policies related to global warming will be notionally deferred and quietly shelved. Innovation, Industry, Science and Research Minister Kim Carr will be allowed to invest in high-profile nonsense such as funding ``the green car''. But the coal industry is unlikely to be closed down or put into a holding pattern. Nor are new local coal-fired power stations going to be prohibited until the technology is developed to capture and sequester carbon. Since the greater part of the funds for the research underpinning that technology is expected to come from the private sector -- and there's a limit to what government can exact by administrative fiat -- as the debate becomes calmer and more evidence-based, business will be increasingly reluctant to outlay money on a phantom problem. Budgetary constraints and rampant inflation provide governments with plenty of excuses for doing as little as possible until a new and better informed consensus emerges on climate. Ross Garnaut could doubtless be asked to extend his carbon trading inquiry for the life of the parliament and to make an interim report in 12 months on the state the science. In doing so, he could fulfil the educative functions of a royal commission and at the same time give himself and the Government a dignified way out of an impasse. Whatever happens in the realm of domestic spin doctoring, economic realities in the developing world were always going to defeat the global warming zealots. Before the election, Kevin Rudd had to concede that we would not adopt climate policies that were contrary to Australian interests unless India and China, emitters on a vastly larger scale, followed suit. However, it has long been obvious that neither country was prepared to consign vast parts of their population to protracted poverty and to embrace low-growth policies on the basis of tendentious science and alarmist computer projections. Even if their governments were convinced that global warming was a problem -- and they clearly aren't -- it's doubtful they could sell the self-denying ordinances we're asking from them to their own people. A likelier scenario would be full-page ads in our broadsheets and catchy local television campaigns paid for by the Indian and Chinese coal, steel and energy industries that buy our raw materials. Their theme would surely be that if many of the West's leading scientific authorities no longer subscribed to catastrophic global warming, why on earth should anyone else.

Gonzaga Debate Institute 2008 Scholars

25 Ice Age

Empirical Evidence ( ) An ice age is engrained in the history of the world. This is more probable. Brennan in 1 (Phil Brennan, Veteran Journalist at Newsmax, www.newsmax.com, Jan 16, 2001) Since by some calculations the current warm period is about 13,000 years old, the next ice age is overdue." "Jeffreys notes the fact that back in the 1970s: 'Many scientists warned of a coming ice age, and with good reason. Although there has been a slight increase in average temperatures during the twentieth century, many regions of the globe have experienced sustained cooling trends.' • The record speaks for itself. In the history of the Earth, ice ages are the norm. They occur regularly as clockwork and as such, must be regarded as immutable laws of nature. It would be sheer folly to believe that this law has somehow been repealed. • We are now between 10,800 and 13,000 years removed from the end of the last ice age. Is it not prudent to expect the onset of another ice age? The historical record shows that this allegedly gentle and loving Mother Earth of ours has demonstrated a tendency to eat her young, and that her appetite for her children grows egregiously voracious as ice ages approach.

( ) Dinosaurs prove that our ecosystem is fine with another 10 degree increase; warming is falsely perpertuated as threatening. An ice age beats warming on timeframe, probability and magnitude. Walker in 2 (Bill; Research Associate at the Shay-Wright Lab at UT, The Laissez-Faire Electronic Times; http://freedom.orlingrabbe.com) The new human powers also defended Earth against the Cold Death that killed Mars. In the time of the dinosaurs, perhaps the peak of biodiversity and ecological exuberance, there was a lot of carbon. The atmosphere was around 1% carbon dioxide. But as the radioactive energy that powers volcanoes runs down, carbon keeps getting trapped in dead organisms and covered by sediments, leaving the biosphere. During the last Ice Age the CO2 level fell below .02%. This is a serious problem for an ecosystem based on photosynthetic plants. Someone (perhaps his third grade teacher) should have told Al Gore; when the CO2 concentration is too low everything photosynthetic dies. In the 1800s, CO2 levels were measured at .028%. Human use of fossil fuels has raised that to .037%; still far below optimum for plant growth, but better. The slight increase in greenhouse effect also gives the Earth a little more protection against ending up like Mars, with our CO2 lying frozen on the ground. (It is, however, a VERY slight increase in greenhouse effect. Most of Earth's greenhouse effect comes from atmospheric water.) The dinosaur eras were 10 degrees warmer than today, and the ecosystem liked that just fine. It's been less than 15,000 years since the last Ice Age. Anyone concerned about the ecology as a whole must worry far more about Ice Age than about greenhouse effect.

Gonzaga Debate Institute 2008 Scholars

26 Ice Age

Studies/Models Prove ( ) Our model is more accurate. Our means of experimenting is actually more partial towards warming and proves that our earth is still cooling making an ice age more probable. Ruddiman in 5 (William, et. Al, Department of Environmental Sciences at the University of Virginia, Quaternary Science) We ran two experiments on the GENESIS 2 climate model (Thompson and Pollard, 1997) as a preliminary assessment of the ‘overdue glaciation’ hypothesis. The atmospheric component of the GENESIS 2 model has 18 vertical levels and a T31 spectral resolution, which corresponds to a grid resolution of 3.751 for calculations of dynamics and precipitation. It has a 21 grid over ocean and land surfaces for calculations of surfaceatmosphere interactions. GENESIS 2 has a 50m static mixed-layer ocean model with parameterized diffusive heat transport, adjusted heat flux in the Norwegian Sea, and interactive sea ice with sea-ice advection forced by interactive surface winds and prescribed ocean currents. We chose this model for several reasons: First, the control-case simulation in GENESIS 2 has a climate sensitivity of 2.5 1C for a CO2 doubling, matching closely the central value of the IPCC estimate, which is based upon results from several models (IPCC, 2001). In general, the model control agrees reasonably well with the NCEP climatological means (Kalnay et al., 1996), especially in Arctic regions where we want to test for possible increases in snow cover. Sea-ice limits also match the climatology closely (Vavrus, 1999). The model has some warm bias over northeastern Canada (upto a few degrees), especially during winter, but its simulated snow cover over Northern Hemisphere continents is quite realistic (Thompson and Pollard, 1997). Second, by resolving topography at 21 (compared to the 2.751 resolution of T42 models), GENESIS 2 ‘sees’ the higher plateau topography on the northeast Canadian margin that is favorable for snow accumulation and glacial inception (Andrews and Mahaffy, 1976). Some elevations in the model exceed 550m and reach within 100m of actual values. Third, the model includes an option that permits an internal lapserate adjustment based upon the difference between the model-resolved elevations and the actual topography. This adjustment brings surface temperature and other surface climate variables even closer to those at actual elevations.

( ) Our experiments actually underrate the ice growth and exclude feedbacks. This microexample still poses threats. Ruddiman in 5 (William, et. Al, Department of Environmental Sciences at the University of Virginia, Quaternary Science) Finally, our ‘snapshot’ experiment only indicates regions where overall mass-balance conditions would permit ice growth, but it does not address how growing ice sheets might have evolved through time. Growing ice sheets have positive feedback effects on local climate, including the elevation/temperature feedback from vertical ice growth, and the albedo feedback from gradually expanding snowfields and lateral ice flow (Andrews and Mahaffy, 1976). Future simulations that incorporate ice, vegetation, and ocean feedbacks, now underway and planned, are likely to enhance the climatic responses to removal of anthropogenic greenhouse gases and enable ice sheets to expand beyond their regions of inception.

Gonzaga Debate Institute 2008 Scholars

27 Ice Age

Natural Phenomena ( ) Ice age is coming, natural phenomena prove. Brennan in 97 (Phil Brennan, Veteran Journalist, “Global Warming or Globaloney?” July 1997; http://www.pvbr.com) The increased weight of the ice pack also depresses the earth's surface at the poles, forcing what John Hamaker called the underlying "gunk" supporting the surface southward at the North Pole and northward at the South Pole. This in turn creates increased volcanic activity (and earthquakes) as the gunk is forced to the earth's surface. (Dr. Kaplan wrote that when the "gunk" is forced up through cracks in the ocean bottom west of the U.S. Pacific litoral, it warms the ocean waters, creating what we call "El Nino.") The resulting volcanic activity heaves great amounts of volcanic dust into the upper atmosphere, blocking even more sunlight from reaching the polar ice caps, thus helping the ice and snow cover to become ever larger and heavier. It is a phemomenon that feeds on itself, and the longer it goes on, the worse it gets. The end results are colder and ever lenthening winters, more and more tectonic activity wreaking havoc all over the globe, more and more destructive storms, and natural disasters of an undreamed of magnitude.

Gonzaga Debate Institute 2008 Scholars

28 Ice Age

Solar Theory ( ) Muller and MacDonald have disproved all previous theories. An ice age is in fact cyclical and another one is on the way. This is the most comparative evidence in the round. Kahn in 97 (Jeffrey Kahn, Berkeley Lab, July 11, 1997; http://www.lbl.gov/Science-Articles/Archive/ice-age-sediments.html) In the paper in Science, the researchers compared the geological record to the climactic cycles that would result from their theory and to that of the competing theory, first published in 1912 by Serbian scientist Milutin Milankovitch. Using a geological fingerprinting technique, Muller and MacDonald found that the climactic changes recorded in the rocks matched their theory but not that of Milankovitch. Milankovitch said the ice ages are caused by variations in sunlight hitting the continents. In his theory, the ice ages are linked to "eccentricity," a very gradual, cyclic change in the shape of the Earth's egg-shaped orbit around the sun that completes a cycle roughly every 100,000 years. Eccentricity changes the Earth's average annual distance from the sun and slightly alters the amount of sunlight hitting the Earth. To visualize the different astronomical cycle that Muller and MacDonald have found to match that of the climatic record, imagine a flat plane with the sun in the center and nine planets circling close to the plane. In fact, all the planets orbit the sun close to such a fixed orbital plane. The Earth's orbit slowly tilts out of this plane and then returns. As Muller first calculated in 1993, the cycle of tilt repeats every 100,000 years.

( ) More evidence. Kahn in 97 (Jeffrey Kahn, Berkeley Lab, July 11, 1997; http://www.lbl.gov/Science-Articles/Archive/ice-age-sediments.html) In their Science paper, Muller and MacDonald examine the geological record of the past million years to see which of the two 100,000-year cycles (eccentricity or tilt) matched the data. They applied a technique called spectral analysis to ocean sediments taken from eight locations around the world, examining the oxygen-18 composition. This isotope is generally accepted to reflect the percentage of the Earth's water frozen in ice. Muller and MacDonald's analysis yields "spectral fingerprints" which can be compared to the predictions of the two theories. Their analysis shows a clear pattern: The fingerprints of the ice ages show a single dominant feature, a peak with a period of 100,000 years. This precisely matches their theory. The fingerprints do not match the expected trio of peaks predicted by the Milankovitch theory. Said Muller, "The mechanism proposed by Milankovitch could be adjusted to explain the cycles of glaciation that occurred prior to one million years ago. However, for the past million years the glacial record is an excellent match to the cycle of tilt."

Gonzaga Debate Institute 2008 Scholars

29 Ice Age

Solar Theory ( ) Tilts in the Earth’s orbit and its elliptical patterns make an ice age the most probable scenario for natural disaster. Kahn in 97 (Jeffrey Kahn, Berkeley Lab, July 11 1997; http://www.lbl.gov/Science-Articles/Archive/ice-age-sediments.html) Recent ice ages -- ten periods of glaciation in the past million years -- are caused by changes in the tilt of the Earth's orbit, according to research published in the July 11 issue of Science magazine. The new analysis also presents strong evidence that another long prevailing theory does not account for these ice ages. Researchers Richard A. Muller of the Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab), and Gordon J. MacDonald of the International Institute for Applied Systems Analysis, Austria, are co-authors of the Science article. Muller and MacDonald report that cyclical changes in the location of the Earth's orbit cause differing quantities of extraterrestrial debris to come into the Earth's atmosphere. This, in turn, results in variations of climate on the planet. Said MacDonald, "As the Earth moves up and down in the plane of the solar system, it runs into various amounts of debris, dust and meteoroids. Our work was an outgrowth of investigations of larger impacts, such as the comet or asteroid that killed the dinosaurs. However, meteoroids and dust are much smaller and more spread-out over time." Muller notes that this new research has important implications for the understanding of the present climate, and for predictions of future climate. "As far as we know," he said, "none of the present climate models include the effects of dust and meteors. And yet our data suggests that such accretion played the dominant role in the climate for the last million years. If we wish to make accurate predictions, we must understand the role played by such material." Despite the current relatively warm climate on Earth, regular recurring epochs of glaciation have dominated the planet for the past million years. Ten times, glaciers have advanced and then retreated with the duration of retreat (and corresponding warmth) frequently lasting not more than 10,000 years. The Earth has been in a warm period for about 10,000 years now.

Gonzaga Debate Institute 2008 Scholars

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Gonzaga Debate Institute 2008 Scholars

31 Ice Age

Interglacial Period Now ( ) Our Earth is currently in an interglacial period of warmth and is threatened by an upcoming ice age; warming needs to accelerate to offset the effects. An ice age could threaten extinction. Marsh in 8 (Gerald, retired physicist from the Argonne National Laboratory and a former consultant to the Department of Defense on strategic nuclear technology and policy, The Coming of a New Ice Age; canadafreepress.com) Contrary to the conventional wisdom of the day, the real danger facing humanity is not global warming, but more likely the coming of a new Ice Age. What we live in now is known as an interglacial, a relatively brief period between long ice ages. Unfortunately for us, most interglacial periods last only about ten thousand years, and that is how long it has been since the last Ice Age ended. How much longer do we have before the ice begins to spread across the Earth’s surface? Less than a hundred years or several hundred? We simply don’t know. Even if all the temperature increase over the last century is attributable to human activities, the rise has been relatively modest one of a little over one degree Fahrenheit — an increase well within natural variations over the last few thousand years. While an enduring temperature rise of the same size over the next century would cause humanity to make some changes, it would undoubtedly be within our ability to adapt. Entering a new ice age, however, would be catastrophic for the continuation of modern civilization. One has only to look at maps showing the extent of the great ice sheets during the last Ice Age to understand what a return to ice age conditions would mean. Much of Europe and North-America were covered by thick ice, thousands of feet thick in many areas and the world as a whole was much colder. The last “little” Ice Age started as early as the 14th century when the Baltic Sea froze over followed by unseasonable cold, storms, and a rise in the level of the Caspian Sea. That was followed by the extinction of the Norse settlements in Greenland and the loss of grain cultivation in Iceland. Harvests were even severely reduced in Scandinavia And this was a mere foreshadowing of the miseries to come. By the mid-17th century, glaciers in the Swiss Alps advanced, wiping out farms and entire villages. In England, the River Thames froze during the winter, and in 1780, New York Harbor froze. Had this continued, history would have been very different. Luckily, the decrease in solar activity that caused the Little Ice Age ended and the result was the continued flowering of modern civilization.

Gonzaga Debate Institute 2008 Scholars

32 Ice Age

Solar Patterns (2022) ( ) We are approaching possibly the peak of inactivity of the sun by 2022. This will substantially cool the Earth to unknown levels and only a warming could offset it. Marsh in 8 (Gerald, retired physicist from the Argonne National Laboratory and a former consultant to the Department of Defense on strategic nuclear technology and policy, The Coming of a New Ice Age; canadafreepress.com) There were very few Ice Ages until about 2.75 million years ago when Earth’s climate entered an unusual period of instability. Starting about a million years ago cycles of ice ages lasting about 100,000 years, separated by relatively short interglacial perioods, like the one we are now living in became the rule. Before the onset of the Ice Ages, and for most of the Earth’s history, it was far warmer than it is today. Indeed, the Sun has been getting brighter over the whole history of the Earth and large land plants have flourished. Both of these had the effect of dropping carbon dioxide concentrations in the atmosphere to the lowest level in Earth’s long history. Five hundred million years ago, carbon dioxide concentrations were over 13 times current levels; and not until about 20 million years ago did carbon dioxide levels dropped to a little less than twice what they are today. It is possible that moderately increased carbon dioxide concentrations could extend the current interglacial period. But we have not reached the level required yet, nor do we know the optimum level to reach. So, rather than call for arbitrary limits on carbon dioxide emissions, perhaps the best thing the UN’s Intergovernmental Panel on Climate Change and the climatology community in general could do is spend their efforts on determining the optimal range of carbon dioxide needed to extend the current interglacial period indefinitely. NASA has predicted that the solar cycle peaking in 2022 could be one of the weakest in centuries and should cause a very significant cooling of Earth’s climate. Will this be the trigger that initiates a new Ice Age? We ought to carefully consider this possibility before we wipe out our current prosperity by spending trillions of dollars to combat a perceived global warming threat that may well prove to be only a will-o-the-wisp.

Gonzaga Debate Institute 2008 Scholars

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33 Ice Age

Gonzaga Debate Institute 2008 Scholars

34 Ice Age

AT: Warming Outweighs ( ) Global Warming is the focal point of the media due to its ability to be controlled or prevented. However, our world is increasingly nearing a cooling period that puts human life on the brink. Brennan in 97 (Phil Brennan, Veteran Journalist, “Global Warming or Globaloney?” July, 1997, http://www.pvbr.com) By May of 1977, it had become evident that the Federal Government was unofficially on board the global warming express. Yet a 1979 poll of top climatologists showed that 81 percent of those responding predicted from a variety of findings that it was cooling , and not warming, that the world faced. Wrote Kaplan: "these findings were drawn from a wide variety of disciplines and methods, from oxygen isotope studies of the ocean bottom strata to carbon 14 studies of tree rings, and included time scales from millions of years to tens of years. "Yet despite the evidence of the thermometer, the great increase of violent climatic variability and drought which accompany cooling, and the opinions of the large majority of scientists, the warming theory continued to be pursued in a manner which received frequent notice in the media, and which produced a stream of letter, brochures, and conferences aimed at the world's political and economic leaders." Kaplan wondered exactly what was behind this refusal of the powers that be even to consider the overwhelming evidence that the climate was cooling and that we are in the final days of an interglacial. He then asked a question that is yet to be answered. "Has the warming theory 'campaign' been the last stand of an arrant scientific ideology? Such a hypothesis can be acceptable to some, but the obvious failing of the theory in the face of global catastrophe argues for a more substantial motivation. "It would pay to investigate this motivation further to consider whether politics has been responsive to poor science or whether economics and politics have made false tools out of science for narrow interest. "If the latter is true the manipulation and subversion of the truth seeking apparatus by political and private interests is, in the present situation, of such extreme malevolence that it ranks as the greatest malfeasance in history. We are headed for a situation where mankind may be forced to confront the question of whether the political mode as we have known it over the past 8,000 years is innately incapable of dealing with serious problems. "The record for the political mode in regard to climate is, after all, dismal.

( ) Warming is politically and economically motivated to be publicized. However, the media has been short-changing substantial scientific claims that an ice age is the real threat. Brennan in 97 (Phil Brennan, Veteran Journalist, “Global Warming or Globaloney?” July, 1997, http://www.pvbr.com) In 1972, a sizeable group of climatologists meeting at Brown University issued letters to the governments of the world in which they warned of a global climatic disaster. Again in 1974 the International Federation of Institutes of Advanced Study issued a similarly grave message to the community of governments from a meeting in Bonn. In 1976 a meeting of 85 climatologists chaired by the late Nobel Laureate Willard Libby and pioneer climatologist Cesare Emiliani put forth another warning which was put into language by Libby. In 1976, the CIA released two reports which it had written in 1974 and which provided the same message in greater detail (but in 1977 military climate researchers, backed up by other government agencies, told the writer that the CIA reports had been discounted by the government). The consensus of the World Climate Conference was reported by Nature as stating that the world has entered a 10,000 year cooling, that the warming theory was complex and questionable, and that the loss of life and economic substance to the climate would increase." Today, almost 18 years later, the U.S. and other governments, whole slews of scientists dependent upon government grants, and the media, remain wedded to the global warming baloney despite mounting evidence that their cherished climate models have failed dismally to support their predictions of global warming -- predictions which seem to change from year to year in frantic efforts to explain why last year's predictions failed to materialize.

Gonzaga Debate Institute 2008 Scholars

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TS: Media Covers GW ( ) GW is a political attempt to cut living standards. Engdahl in 8 (F. William; Writer for Centre of Research on Globalization; Global Warming gets the Cold Freeze; April 9) The recent Global Warming hysteria is in reality a geopolitical push by leading global elite circles to find a way to get the broader populations to willingly accept drastic cuts in their living standards, something that were it demanded without clear reason by politicians, would spark strikes and protest. The UN’s latest IPCC report on Global Warming calls for diverting a huge 12% of global GDP to “prevent the harmful effects of climate change.” The UN report, for example, estimated that its recommendations to reduce certain manmade emissions would cost about $2,750 per family per year in the price of energy.

Gonzaga Debate Institute 2008 Scholars

36 Ice Age

AT: GW  IA (Milankovitch Proves) ( ) GW can not cause an ice age; this theory has been debunked. An ice age is caused by Earth’s rotation and its orbit. Lomborg in 4 (Bjorn Lomborg, Editor of the Skeptical Environmentalist, May 22, 2004; www.sepp.org) "There's more truth than hype," the film-makers promise in their publicity. The German director, Roland Emmerich, claims he tried to present us with a valuable fund of scientific information. The film's website provides links to news stories published in February about "a secret report prepared by the Pentagon" which warned that climate change would "lead to global catastrophe costing millions of lives". What this publicity does not reveal is that the Pentagon report was merely a hypothetical worst-case scenario - and one that has already been thoroughly debunked. In fact, the respected magazine Science has reviewed this Pentagon report and the alleged scientific support for The Day After Tomorrow and concludes that "it is highly unlikely that global warming will lead to a widespread collapse" of the Gulf Stream, and "it is safe to say that global warming will not lead to the onset of a new Ice Age". In Nature, another highly-respected scientific journal, a researcher finds that halting the Gulf Stream would be impossible, arguing that "the only way to produce an ocean circulation without the Gulf Stream would be to turn off the wind system or stop the Earth's rotation, or both."

Gonzaga Debate Institute 2008 Scholars

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AT: GW  IA (Volcanoes) ( ) The interference with the sun that causes cooling is primarily caused by sulfurcompounded particulates. Volcanoes are the biggest cause of this medium. They will not win a bigger internal link to cooling. Tkachuck in 5 (Richard; Geoscience Research Institute; November; The Little Ice Age; http://www.grisda.org) While it is relatively easy to find evidence for a general cooling trend, it is more difficult to define the cause(s) for this phenomena. More likely, it is the result of several factors. Before we examine these, a brief discussion of the energy structure of Earth is necessary. The sun, obviously, is the source of energy for this planet. Fluctuations in the amount of energy absorbed by the Earth will cause variations in the total amount of heat retained or lost. Particulate matter in the atmosphere which blocks some of the incoming energy has been observed to promote a cooling trend for short periods of time. This particulate matter until the present century was largely a result of volcanic activity. Recent industrial pollution is proposed as a cause of the recent cooling trend that began in the 1950s. The explosions of volcanoes in the 19th century have been correlated with a subsequent coolness in the weather in the following years. The explosion of Tambora in 1815 which catapulted 150 cubic kilometers of rock dust is given credit for "the year without summer" in 1816. The explosion of Krakatoa in 1883 presumably lowered the mean earth temperature about 1ºC for several years (Rampino and Self 1982). The presence of this particulate matter may increase the amount of precipitation, because the ejected material acts as condensation nuclei around which water droplets can form. Without these nuclei the air becomes supersaturated. In addition to particulate matter being ejected, perhaps even greater absorption of the sun's rays is due to absorption by ejected sulfur compounds (Pollack et al. 1976). These sulfur compounds eventually form fine droplets of sulfuric acid which may remain suspended for years in the upper atmosphere, forming large clouds which reduce the penetration of the sun's energy. Because of the ejection of an aerosol into the upper atmosphere by the volcano El Chichon which exploded in Mexico in 1982, several meteorologists predicted a winter colder than usual for 1982 (Kerr 1982). Whether the action of volcanoes is responsible for a cooling that lasted several hundred years is debatable. It seems unlikely that a single volcanic event would be great enough to cause such a cooling effect. History does not record such a single large event but does record many smaller events which occurred in various parts of the world at frequent intervals.

Gonzaga Debate Institute 2008 Scholars

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AT: GW  IA (Little Ice Age) ( ) The Little Ice Age proves that human-induced warming doesn’t accelerate cooling; IT STOPS IT. We have the only empirical example in-round making our evidence most valid. Tkachuck in 5 (Richard; Geoscience Research Institute; November; The Little Ice Age; http://www.grisda.org) Warming of the atmosphere can result from an increase in the CO2 levels. The effect of CO2 on climate is a topic of considerable interest at the present time (see Revelle 1982 as an example of support; Madden and Ramanthan 1980 for negative evidence). Briefly, as the sun shines on Earth, unabsorbed light waves are reflected back into the atmosphere in the form of longer wavelength energy. The CO2 in the atmosphere absorbs some of this infrared radiation, resulting in increased molecular motion or heat which in turn causes a warming of the atmosphere and ultimately the earth itself. This "greenhouse effect" has provoked some to become alarmists fearing that warming due to increased CO2 in the atmosphere as a result of burning fossil fuels will cause the polar caps to melt, thereby raising the average level of the oceans and also increase the area of deserts. It might be suggested that the Industrial Revolution's intensified burning of coal and wood increased the atmospheric CO2 sufficiently to hasten the end of the Little Ice Age.

Gonzaga Debate Institute 2008 Scholars

39 Ice Age

AT: GW  IA (Solar Patterns) ( ) An ice age is not human-induced. It’s a natural cycle that has an indirect-causal relationship with solar activity. Our evidence cites specific examples in history. Tkachuck in 5 (Richard; Geoscience Research Institute; November; The Little Ice Age; http://www.grisda.org) Another theory for the cause of the Little Ice Age centers not on the atmospheric restriction of the amount of energy flowing into the earth, but on the concept that the sun itself is variable in its energy production. It is estimated that a fluctuation of only a few tenths of 1% in energy output would be sufficient to produce significant changes in climate (Budyko 1969). An interesting coincidence held meaningful by many is the absence of sunspot activity through most of the latter and most severe period of the Little Ice Age (Eddy 1976). While accurate astronomical records are increasingly difficult to obtain as one moves back in history, there is yet a convincing amount of data which allows one to have confidence in the historical sunspot record. At present sunspots — large areas of reduced surface temperature and increased magnetic field strength — increase and decrease numerically through an approximately 11-year cycle. These changes in solar magnetic field also affect the rate at which 14C is produced on earth and may provide a retrospective record of variations in sunspot activity (Figure 1g). Observations from the 1700s to the present have established a remarkable regularity in sunspot activity. Over the years there have been numerous attempts to correlate these cycles with weather cycles. While sunspot/weather analysis has not produced a consistent correlation, it is widely accepted that sunspot activity does indeed influence the weather. However, an interesting near absence of sunspot activity is found in the early decades of the 1600s extending into the first decade of the 1700s. This time corresponds remarkably with the coldest period of the Little Ice Age.

Gonzaga Debate Institute 2008 Scholars

40 Ice Age

AT: NAC Shutdown (General) ( ) There is no direct relation between warming and Arctic freshwater balance, we need to increase our studies of the NAO and NAM. Science proves. MBL 6 (Marine Biological Lab, North Atlantic Ocean freshening could weaken Gulf Stream, August, mongabay.com) The team's comparison of freshwater sources and ocean sink records revealed that over the last half century changes in freshwater inputs and ocean storage occurred not only in conjunction with one another, but in synchrony with rising air temperatures and an amplifying North Atlantic Oscillation (NAO), a climatic phenomenon that has strong impacts on weather and climate in the North Atlantic region and surrounding continents, and the associated Northern Annular Mode (NAM) index. Peterson and his colleagues contend that the interplay between the NAO and NAM, and continued rising temperatures from global greenhouse warming, will likely determine whether the Arctic and North Atlantic Oceans will continue to freshen. But the scientists caution that the difficultly in predicting fluctuations in atmospheric circulation makes it impossible to know where we might be headed. "Atmospheric modes of circulation such as the NAO and NAM exert a great deal of control on net precipitation in the ocean and even on regional temperatures, and hence ice melt as well," says Peterson. "But what drives the NAO is the $64,000 question. Our inability to predict trends in the NAO/NAM means that, even if we could predict global warming very well, a large degree of uncertainty will remain in any forecasts of the decadal-centennial trajectories of the Arctic freshwater balance."

Gonzaga Debate Institute 2008 Scholars

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AT: NAC (Keenlyside Model) ( ) Keenlyside just enhanced the accuracy of this study with a new model that can simulate natural variations in the MOC. This proves that the changes in the North Atlantic current are natural. This offsets warming. Our evidence is the most recent and comparative. Wood in 8 (Richard, Writer for Nature Report, Scientist, Researcher; Climate change: Natural ups and downs; April 30,http://www.nature.com) The effects of global warming over the coming decades will be modified by shorter-term climate variability. Finding ways to incorporate these variations will give us a better grip on what kind of climate change to expect. Climate change is often viewed as a phenomenon that will develop in the coming century. But its effects are already being seen, and the Intergovernmental Panel on Climate Change recently projected that, even in the next 20 years, the global climate will warm by around 0.2 °C per decade for a range of plausible greenhouse-gas emission levels1. Many organizations charged with delivering water and energy resources or coastal management are starting to build that kind of warming into their planning for the coming decades. A confounding factor is that, on these timescales, and especially on the regional scales on which most planning decisions are made, warming will not be smooth; instead, it will be modulated by natural climate variations. In this issue, Keenlyside et al. (page 84)2 take a step towards reliably quantifying what those ups and downs are likely to be. Their starting point is the ocean. On a timescale of decades, this is where most of the 'memory' of the climate system for previous states resides. Anomalously warm or cool patches of ocean can be quite persistent, sometimes exchanging heat with the atmosphere only over several years. In addition, large ocean-current systems can move phenomenal amounts of heat around the world, and are believed to vary from decade to decade. To know and predict the state of the ocean requires an approach similar to weather forecasting: one sets up (initializes) a mathematical model of the climate system using observations of the current state, and runs it forwards in time for the desired forecast period. With a given climate model, enough observations to set the ball rolling and a large-enough computer to move it onwards, the exercise is conceptually straightforward. But does it actually produce anything useful? We don't expect to be able to predict the details of the weather at a particular time several years in the future: that kind of predictability runs out after a week or two. But even predicting, say, that summers are likely to be unusually wet during the coming decade would be useful to many decision-makers. Only recently, with the study from Keenlyside et al.2 and another from researchers at my own institution5, have climate modellers begun to explore whether such predictions are possible.Keenlyside and colleagues' model uses a very simple ocean initialization method in which they add heat to or remove it from the ocean surface until sea surface temperatures across the globe are close to observed values. They use their model to produce a set of retrospective 'forecasts' starting from earlier states, which they test against what actually happened. Their system produces refined temperature predictions a decade ahead for large parts of Europe and North America. The enhanced accuracy of the model seems to stem from a greater ability to simulate natural variations in the meridional overturning circulation (MOC). This is a giant conveyor belt that brings warm water northwards into the North Atlantic, releases its heat to the atmosphere, and returns the cooled water to the south. There is evidence that the strength of this circulation can fluctuate naturally over periods of decades3; when it is strong, the climate in the North Atlantic region passes through a warm phase. The authors use their model to predict that the MOC will weaken over the next decade, with a resultant cooling effect on climate around the North Atlantic. Such a cooling could temporarily offset the longer-term warming trend from increasing levels of greenhouse gases in the atmosphere. That emphasizes once again the need to consider climate variability and climate change together when making predictions over timescales of decades (Fig. 1).

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AT: NAC (Cooling Inev.) ( ) Their conclusions about the NAC are wrong. This cooling is part of a natural, inevitable cycle that had no causal relationship with warming. Our evidence synthesizes the work of multiple scientists making it the most comparative and most recent. Efstathiou in 8 (Jim., Reporter, Ocean Cooling to Briefly Halt Global Warming, Researchers Say, Bloomberg.com, April 30) Parts of North America and Europe may cool naturally over the next decade, as shifting ocean currents temporarily blunt the global-warming effect caused by mankind, Germany's Leibniz Institute of Marine Sciences said. Average temperatures in areas such as California and France may drop over the next 10 years, influenced by colder flows in the North Atlantic, said a report today by the institution based in Kiel, Germany. Temperatures worldwide may stabilize in the period. The study was based on sea-surface temperatures of currents that move heat around the world, and vary from decade to decade. This regional cooling effect may temporarily neutralize the long- term warming phenomenon caused by heat-trapping greenhouse gases building up around the earth, said Richard Wood, a research scientist at the Met Office Hadley Centre, a U.K. provider of environmental and weather-related services. ``Those natural climate variations could be stronger than the global-warming trend over the next 10-year period,'' Wood said in an interview. ``Without knowing that, you might erroneously think there's no global warming going on.'' The Leibniz study, co-written by Noel Keenlyside, a research scientist at the institute, will be published in the May 1 issue of the journal Nature. ``If we don't experience warming over the next 10 years, it doesn't mean that greenhouse-gas warming is not with us,'' Keenlyside said in an interview. ``There can be natural fluctuations that may mask climate change in the short term.''

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AT: NAC (Wind-cycles) ( ) Extensive studies prove that it’s not the ice melt but rather the wind circulation that drives currents. This evidence is more comparative because it takes into account the past 40-year wind cycle. Gunter in 8 (Lorne,Canadian Centre for Libertarian Studies; Welcome to the new ice age; nationalpost.com) Snow cover over North America and much of Siberia, Mongolia and China is greater than at any time since 1966. The U.S. National Climatic Data Center (NCDC) reported that many American cities and towns suffered record cold temperatures in January and early February. According to the NCDC, the average temperature in January "was -0.3 F cooler than the 1901-2000 (20th century) average." China is surviving its most brutal winter in a century. Temperatures in the normally balmy south were so low for so long that some middle-sized cities went days and even weeks without electricity because once power lines had toppled it was too cold or too icy to repair them. There have been so many snow and ice storms in Ontario and Quebec in the past two months that the real estate market has felt the pinch as home buyers have stayed home rather than venturing out looking for new houses. In just the first two weeks of February, Toronto received 70 cm of snow, smashing the record of 66.6 cm for the entire month set back in the pre-SUV, pre-Kyoto, pre-carbon footprint days of 1950. And remember the Arctic Sea ice? The ice we were told so hysterically last fall had melted to its "lowest levels on record? Never mind that those records only date back as far as 1972 and that there is anthropological and geological evidence of much greater melts in the past. The ice is back. Gilles Langis, a senior forecaster with the Canadian Ice Service in Ottawa, says the Arctic winter has been so severe the ice has not only recovered, it is actually 10 to 20 cm thicker in many places than at this time last year. OK, so one winter does not a climate make. It would be premature to claim an Ice Age is looming just because we have had one of our most brutal winters in decades. But if environmentalists and environment reporters can run around shrieking about the manmade destruction of the natural order every time a robin shows up on Georgian Bay two weeks early, then it is at least fair game to use this winter's weather stories to wonder whether the alarmist are being a tad premature. And it's not just anecdotal evidence that is piling up against the climate-change dogma. According to Robert Toggweiler of the Geophysical Fluid Dynamics Laboratory at Princeton University and Joellen Russell, assistant professor of biogeochemical dynamics at the University of Arizona -- two prominent climate modellers -- the computer models that show polar ice-melt cooling the oceans, stopping the circulation of warm equatorial water to northern latitudes and triggering another Ice Age (a la the movie The Day After Tomorrow) are all wrong. "We missed what was right in front of our eyes," says Prof. Russell. It's not ice melt but rather wind circulation that drives ocean currents northward from the tropics. Climate models until now have not properly accounted for the wind's effects on ocean circulation, so researchers have compensated by over-emphasizing the role of manmade warming on polar ice melt. But when Profs. Toggweiler and Russell rejigged their model to include the 40-year cycle of winds away from the equator (then back towards it again), the role of ocean currents bringing warm southern waters to the north was obvious in the current Arctic warming. Last month, Oleg Sorokhtin, a fellow of the Russian Academy of Natural Sciences, shrugged off manmade climate change as "a drop in the bucket." Showing that solar activity has entered an inactive phase, Prof. Sorokhtin advised people to "stock up on fur coats."

Gonzaga Debate Institute 2008 Scholars

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AT: NAC (Solar Inactivity) ( ) Studies prove that the current theory is obsolete. Climactic changes are primarily due to solar patterns that have been highly inactive in recent years. Engdahl in 8 (F. William; Writer for Centre of Research on Globalization; Global Warming gets the Cold Freeze; April 9) Russian climatologists believe recent weather changes around the globe are results of solar activity and not man-made emissions. Oleg Sorokhtin, a fellow of the Russian Academy of Natural Sciences, calls the argument for man-made climate change "a drop in the bucket." His research shows that now the recent very active solar activity has entered an inactive phase. He advised people to "stock up on fur coats." Kenneth Tapping of Canada’s National Research Council, who oversees a giant radio telescope focused on the sun, is convinced we are in for a long period of severely cold weather if sunspot activity does not pick up soon. The last time the sun was this inactive, Earth suffered the Little Ice Age that lasted about five centuries and ended in 1850. Crops failed through killer frosts and drought. Famine, plague and war were widespread. Harbours froze, so did rivers, and trade ceased.

( ) Hard science proves that between the ultimatum of thermohaline and solar inactivity; the predominant cause of the little ice age was solar cycles. Leake in 5 (Johnathan, Science Editor for The Sunday, Britain faces big chill as ocean current slows, May 8) In discussing the implications of their findings for the thermohaline circulation of the ocean and its role in facilitating global climate change, Berstad et al. forthrightly express their opinion that the Little Ice Age was of global extent, which is something that is vociferously denied by climate alarmists. Berstad et al. note, for example, that "the evidence of the Little Ice Age as a global event, as documented in changes in the atmospheric circulation in the Southern (Kreutz et al., 1997) and Northern Hemisphere (O'Brian et al., 1995), suggests that large-scale changes in ocean and atmospheric circulation were involved," additionally stating that "the findings of increased deep-water formation in the Southern Ocean during the Little Ice Age by Broecker (1999, 2001) and Broecker et al. (1999) further support this interpretation of variability in the thermohaline circulation. In summation, Berstad et al. suggest that the Little Ice Age was (1) real, (2) really cold, and (3) solar-induced, while they report corroborating evidence for its global extent.

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AT: NAC (Studies) ( ) Their studies are vague and indefinite. Readings of the NAC have barely scratched the surface of full-comprehension. There is no way to fully decipher the results for the next couple of decades. They have no credibility to their claims. Wood in 8 (Richard, Writer for Nature Report, Scientist, Researcher; Climate change: Natural ups and downs; April 30,http://www.nature.com) These results provide encouragement that such predictions may be possible, but substantial points require clarification. Chief among these is whether the authors' initialization, which takes into account only sea surface temperatures, is in fact suitable to characterize the state of the MOC. The MOC extends to a depth of several kilometres and depends not just on temperature, but on the salinity of the ocean water. The answer will be some time in coming, as regular monitoring of the MOC has only just begun4. In addition, there is the fact that, although it seems to improve predictions around the North Atlantic compared with models that have no initialization, the model's accuracy is less over other regions such as the tropical North Atlantic and central Africa. This might be because of deficiencies in the climate model or in the initialization procedure. The two studies that have attempted decadal-scale modelling to date differ in the regions for which their predictions are most accurate, so clearly there is much still to be understood.

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AT: NAC  IA ( ) The impact of the halting of the NAC would be insignificant and offset by GW. NASA 1 (Ocean Circulation Shut Down by Melting Glaciers After Last Ice Age, November 19, /www.giss.nasa.gov) When the model was adjusted to make the circulation weaker than it is today, cessation of the Gulf Stream took only 150-200 years, matching current estimates based on paleo-climate records . But when freshwater gets mixed with the salty water in the North Atlantic, it makes the water less dense and slows the overturning process and the ocean circulation. While the study finds that freshwater input could slow and stop overturning, this would not stop the Gulf Stream entirely. That's because the stream is partially pushed by winds. As a result, the model shows the reduced Gulf Stream would only transport about half as much heat northward, thereby cooling Western Europe. Were this to occur in a global warming scenario, it would act to partly counter the effects of projected greenhouse warming in parts of Western Europe. Many scientists suspect more rainfall in parts of the Northern Hemisphere during this century as a result of greenhouse warming. That's because warmer temperatures increase the atmosphere's capacity to carry water. "The North Atlantic circulation may already be weakening due to freshwater rainfall additions associated with global warming," Rind said. But the model shows a number of inconsistencies with previous studies on the last ice age. Those studies speculate that once freshwater stopped flowing, the ocean circulation would return within only a few decades, matching a rapid warming seen in the climate record. The model finds that deepwater circulation does not return for at least hundreds of years when the freshwater additions end. Also contrary to observations, the model showed cooling throughout the Northern Hemisphere; during the last ice age, the majority of the United States land mass did not appear to cool.

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AT: Polar Precipitation ( ) Warming will decrease polar snow and ice – precipitation will not offset this effect. Overland 07+ [James, Pacific Marine Environmental Laboratory, John E. Walsh, International Arctic Research Center, Muyin Wang, Joint Institute for the Study of the Atmosphere and Ocean, “Why Are Ice and Snow Changing?” from after April 6] An important positive feedback is the ice and snow albedo feedback (see also Chapters 2, 4 and 5). Sea ice and snow have high albedo. This means that they reflect most of the solar radiation. With warmer polar temperatures, the area of sea ice and snow cover decreases, exposing new expanses of ocean and land surfaces that absorb an increased amount of solar radiation. This increase of total absorbed solar radiation contributes to continued and accelerated warming. Many IPCC climate models suggest a major loss in sea ice cover by the mid 21st century caused by albedo feedback from shrinking snow cover and increased open water areas in summer15.

( ) Changes in Antarctic sea-ice cover does not affect climate. EPA 07 [Climate Change – Health and Environmental Effects, “Polar Regions,” December 17, http://www.epa.gov/climatechange/effects/polarregions.html] Antarctica has experienced significant retreat and collapse of ice shelves, the result of regional warming. The loss of these ice shelves has few direct impacts on sea level and global climate. Because the ice shelves were floating, their melting does not directly add to sea level rise. They usually are replaced by sea-ice cover, so overall albedo (reflectivity) changes very little (IPCC, 2007a).

( ) Even if Antarctic ice sheets expand the West Antarctic ice sheet will not – polar precipitation is irrelevant. EPA 07 [Climate Change – Health and Environmental Effects, “Polar Regions,” December 17, http://www.epa.gov/climatechange/effects/polarregions.html] As climate change continues, most of the land-based Antarctic ice sheet is actually likely to thicken if projected warming increases snowfall. There is a small risk, however, that the West Antarctic ice sheet will retreat in coming centuries. This is because the West Antarctic ice sheet is moored in an oceanic basin, where slippery mud covers the basin floor. This unique setting makes the ice sheet potentially unstable (IPCC, 2007a).

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AT: Milankovitch Wrong ( ) The Devils Hole theory corroborates Milankovitch’s theory by providing evidence under a timeframe that complies with low eccentricity and obliquity. Pitman 6 (Sean, M.D., Loma Linda University School of Medicine, Milankovitch Cycles, http://www.detectingdesign.com/milankovitch.html) This paper was followed by a rebuttal from Cesare Emiliani, a well known and outspoken supporter of MT entitled, "Milankovitch theory verified". Emiliani wrote: "Broecher compares terminations (the transitions between glacial and interglacial conditions) in deep-sea cores with the recently published delta18O curve from Devils Hole, Nevada to question the validity of the Milankovitch theory. Terminations, transitional episodes that extend through time, are poor time markers for the correlation of Pleistocene sections. The maxima (hypsithermals) and especially the minima (bathythermals) in the isotope curves are much sharper and thus afford a more precise correlation. . .Astronomical parameters recalculated by Berger show that at that time both obliquity [41ka period] and eccentricity [100ka period] were low. If these conditions were responsible for the last ice age, one would expect that similar conditions could be responsible for the preceding ice ages. The table compares the times when these conditions recurred during the past half million years with the ages from Devils Hole. Because the two time scales are independent of each other, their close similarity suggests a common cause which, one would suspect, is the Milankovitch mechanism. Thus, far from invalidating Milankovitch, as maintained by Winograd et al. and by Broecker, the Devils Hole chronology appears to provide support. Support is also suggested by an analysis of the Devils Hole spectrum." 2

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Gonzaga Debate Institute 2008 Scholars

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GW  Ice Age (Stagnant NAC) ( ) The water displacement in the North Atlantic current is brought upon by global warming. We control the biggest internal link to an ice age. Pearce in 5 (Fred, Environment and Development Consultant, Failing Ocean Current raises fears of mini ice age, newscientist.com)

The ocean current that gives western Europe its relatively balmy climate is stuttering, raising fears that it might fail entirely and plunge the continent into a mini ice age. The dramatic finding comes from a study of ocean circulation in the North Atlantic, which found a 30% reduction in the warm currents that carry water north from the Gulf Stream. The slow-down, which has long been predicted as a possible consequence of global warming, will give renewed urgency to intergovernmental talks in Montreal, Canada, this week on a successor to the Kyoto Protocol. Harry Bryden at the National Oceanography Centre in Southampton, UK, whose group carried out the analysis, says he is not yet sure if the change is temporary or signals a long-term trend. "We don’t want to say the circulation will shut down," he told New Scientist. "But we are nervous about our findings. They have come as quite a surprise." No one-off The North Atlantic is dominated by the Gulf Stream – currents that bring warm water north from the tropics. At around 40° north – the latitude of Portugal and New York – the current divides. Some water heads southwards in a surface current known as the subtropical gyre, while the rest continues north, leading to warming winds that raise European temperatures by 5°C to 10°C. But when Bryden’s team measured north-south heat flow last year, using a set of instruments strung across the Atlantic from the Canary Islands to the Bahamas, they found that the division of the waters appeared to have changed since previous surveys in 1957, 1981 and 1992. From the amount of water in the subtropical gyre and the flow southwards at depth, they calculate that the quantity of warm water flowing north had fallen by around 30%. When Bryden added previously unanalysed data – collected in the same region by the US government’s National Oceanic and Atmospheric Administration – he found a similar pattern. This suggests that his 2004 measurements are not a one-off, and that most of the slow-down happened between 1992 and 1998. The changes are too big to be explained by chance, co-author Stuart Cunningham told New Scientist from a research ship off the Canary Islands, where he is collecting more data. "We think the findings are robust."

( ) The climactic responses to warming have caused an increased ice build-up in the Arctic causing colder temperatures in the world. Only our evidence distinguishes between the two southward flows in the North Atlantic making it the most comparative in the round. Pearce in 5 (Fred, Environment and Development Consultant, Failing Ocean Current raises fears of mini ice age, newscientist.com)

Bryden speculates that the warming may have been part of a global temperature increase brought about by man-made greenhouse warming, and that this is now being counteracted by a decrease in the northward flow of warm water. After warming Europe, this flow comes to a halt in the waters off Greenland, sinks to the ocean floor and returns south. The water arriving from the south is already more saline and so more dense than Arctic seas, and is made more so as ice forms. Predicted shutdown. But Bryden’s study has revealed that while one area of sinking water, on the Canadian side of Greenland, still seems to be functioning as normal, a second area on the European side has partially shut down and is sending only half as much deep water south as before. The two southward flows can be distinguished because they travel at different depths. Nobody is clear on what has gone wrong. Suggestions for blame include the melting of sea ice or increased flow from Siberian rivers into the Arctic. Both would load fresh water into the surface ocean, making it less dense and so preventing it from sinking, which in turn would slow the flow of tropical water from the south. And either could be triggered by man-made climate change. Some climate models predict that global warming could lead to such a shutdown later this century. The last shutdown, which prompted a temperature drop of 5°C to 10°C in western Europe, was probably at the end of the last ice age, 12,000 years ago. There may also have been a slowing of Atlantic circulation during the Little Ice Age, which lasted sporadically from 1300 to about 1850 and created temperatures low enough to freeze the River Thames in London.

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Link Turn: GW  Ice Age (Stagnant NAC) ( ) Global warming could cause two potentially damaging scenarios concerning the NAC, both resulting in economic collapse, massive famines, and culminating in extinction. Gagosian in 8 (Robert B., President and Director of Woods Hole Oceanographic Institution, May 7, http://www.whoi.edu) Scientists are investigating whether changes in ocean circulation may have played a role in causing or amplifying the “Little Ice Age” between 1300 and 1850. This period of abruptly shifting climate regimes and more severe winters had profound agricultural, economic, and political impacts in Europe and North America and changed the course of history. During this era, the Norse abruptly abandoned their settlements in Greenland. The era is captured in the frozen landscapes of Pieter Bruegel’s 16th-century paintings and in the famous painting of George Washington’s 1776 crossing of an icebound Delaware River, which rarely freezes today. But the era is also marked by persistent crop failures, famine, disease, and mass migrations. “The Little Ice Age,” wrote one historian, “is a chronicle of human vulnerability in the face of sudden climate change.”8 Societies are similarly vulnerable to abrupt climate changes that can turn a year or two of diminished rainfall into prolonged, severe, widespread droughts. A growing body of evidence from joint archaeological and paleoclimatological studies is demonstrating linkages among ocean-related climate shifts, “megadroughts,” and precipitous collapses of civilizations, including the Akkadian empire in Mesopotamia 4,200 years ago, the Mayan empire in central America 1,500 years ago, and the Anasazi in the American Southwest in the late 13th century.9 Rapid changes in ocean circulation associated with the abrupt North Atlantic cooling event 8,200 years ago have been linked with simultaneous, widespread drying in the American West, Africa, and Asia.10 Regional cooling events also have been linked with changes in the Southwest Asian monsoon, whose rains are probably the most critical factor supporting civilizations from Africa to India to China.11What future climate scenarios should we consider? The debate on global change has largely failed to factor in the inherently chaotic, sensitively balanced, and threshold-laden nature of Earth’s climate system and the increased likelihood of abrupt climate change. Our current speculations about future climate and its impacts have focused on the Intergovernmental Panel on Climate Change, which has forecast gradual global warming of 1.4° to 5.8° Celsius over the next century. It is prudent to superimpose on this forecast the potential for abrupt climate change induced by thermohaline shutdown. Such a change could cool down selective areas of the globe by 3° to 5° Celsius, while simultaneously causing drought in many parts of the world. These climate changes would occur quickly, even as other regions continue to warm slowly. It is critical to consider the economic and political ramifications of this geographically selective climate change. Specifically, the region most affected by a shutdown—the countries bordering the North Atlantic—is also one of the world’s most developed. The key component of this analysis is when a shutdown of the Conveyor occurs. Two scenarios are useful to contemplate:Scenario 1: Conveyor slows down within next two decades. Such a scenario could quickly and markedly cool the North Atlantic region, causing disruptions in global economic activity. These disruptions may be exacerbated because the climate changes occur in a direction opposite to what is commonly expected, and they occur at a pace that makes adaptation difficult. Scenario 2: Conveyor slows down a century from now. In such a scenario, cooling of the North Atlantic region may partially or totally offset the major effects of global warming in this region. Thus, the climate of the North Atlantic region may rapidly return to one that more resembles today’s—even as other parts of the world, particularly lessdeveloped regions, experience the unmitigated brunt of global warming. If the Conveyor subsequently turns on again, the “deferred” warming may be delivered in a decade.

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Link Turn: GW  Ice Age (Stagnant NAC) ( ) Global warming is causing major problems with the NAC. This evidence proves that gw is the direct cause for these temperature and salinity variations and its substantiated with credible scientific models. Owen in 5 ( James, National Geographic News Correspondent, "Mini Ice Age" May Be Coming Soon, Sea Study Warns, November 30, lexis) Chilling new evidence from the Atlantic Ocean is raising fears that western Europe could soon be gripped by a mini ice age. Global warming is slowing down the ocean current that carries warm waters from the tropics to the North Atlantic, scientists say. In the 2004 eco-disaster movie The Day After Tomorrow, a similar scenario spurred sudden, catastrophic climate change, with much of Europe and the United Stated transformed into frozen wastelands within days. That scenario remains far-fetched. But British scientists say their new findings indicate that the threat looks all too real for northern Europe and marine animals. Researchers at the National Oceanography Centre in Southampton, England, found that the flow of warm ocean currents toward northwest Europe has declined by 30 percent since the 1950s. The research, to be published tomorrow in the journal Nature, is based on data collected in a great swath of the Atlantic between West Africa and Florida. Led by oceanographer Harry Bryden, the team detected other key changes in the overall Atlantic circulation system. For one thing, there appears to be a 50 percent reduction in the amount of cold, deep water flowing from the North Atlantic to the tropics, the team says. Also, the researchers found a 50 percent increase in currents circulating within subtropical seas without reaching higher latitudes. More warm waters, that is, are staying put in the tropics. The study supports computer model predictions suggesting that global warming will switch off the North Atlantic current in the next 50 to 100 years. (See "Global Warming May Alter Atlantic Currents, Study Says.") "This provides the first evidence that such a slowdown is actually occurring," said Detlef Quadfasel, oceanographer at the University of Hamburg in Germany. Quadfasel, who was not involved in the study, says the British team's findings aren't conclusive. They are, he said, based on limited samples of water salinity and temperature collected over five decades. Still, Quadfasel said, "This observation is really important, even though it's at the limit of accuracy. The main message, I think, is right." Many scientists have predicted this effect. Global warming already appears to be injecting more fresh water into polar seas due to increased precipitation and the melting of the Greenland ice cap. This freshening of the North Atlantic current makes its waters less dense —so they don't sink down to depths at which they would then be transported back south. As result, the circulation stalls, with warmer water no longer being drawn north. Measurements of salinity levels in the North Atlantic over the last 50 years show "a significant trend toward lower salinity all over the place," Quadfasel said. Evidence from prehistoric times shows that it is possible for northern air temperatures to drop by 10ºC (18ºF) within decades. These abrupt changes are intimately linked to switches in ocean circulation, experts say.

( ) The disastrous slowing of the NAC is seen as the ‘fingerprint of global warming’ making warming the biggest factor leading our planet to an ice age. Lean 4 (Geoffrey, Environment Editor , Global Warming Will Plunge Britain Into New Ice Age 'Within Decades', http://news.independent.co.uk/ ) The scientists, who studied the composition of the waters of the Atlantic from Greenland to Tierra del Fuego, found that they have become "very much" saltier in the tropics and subtropics and "very much" fresher towards the poles over the past 50 years. This is alarming because the Gulf Stream is driven by cold, very salty water sinking in the North Atlantic. This pulls warm surface waters northwards, forming the current. The change is described as the "fingerprint" of global warming. As the world heats up, more water evaporates from the tropics and falls as rain in temperate and polar regions, making the warm waters saltier and the cold ones fresher. Melting polar ice adds more fresh water. Apparently, similar "flips" have occurred before and caused cool periods in Europe. Due to the non linear nature of such a change, the cooling could come as fast as a decade or two. Watch out.

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Link Turn: GW  Ice Age (Stagnant NAC) ( ) The NAC brings Europe heat the equivalent of 100,000 large power stations. Its halt could drop the average temperature by more than 10 degrees greatly changing the ecosystem and environment. Hearld 4 (Morning Herald, Sydney (Australia), World's Achilles heels, Oct. 26, 2004, http://www.heatisonline.org) The North Atlantic current is one of the strongest ocean currents in the world. It works like a conveyor belt. Surface water in the North Atlantic is first cooled by westerly winds from North America, making the water denser and saltier so it sinks to the ocean floor before moving towards the equator. Driven by winds and replacing the cold water moving south, warm water from the Gulf of Mexico moves upward into the Atlantic. The effect of the current on climate is dramatic. It brings to Europe the equivalent of 100,000 large power stations' worth of free heating, propping up temperatures by more than 10C in some parts. Global warming could change all that, though not quickly. Computer models predict that as global warming increases, so will rainfall in the North Atlantic. Gradually the heavier rains will dilute the sea water and make it less likely to sink, a process that could eventually bring the whole conveyor to a halt. "It won't happen in a matter of weeks, like in the movie The Day After Tomorrow, but it could happen over a few decades," Schellnhuber says. In the past 50,000 years, the current has stopped at least seven times. Collapse of the North Atlantic current would hit Iceland, Scotland and Norway the hardest; temperatures there could drop 10C or more.

( ) Additions of fresh water via glacial melting and precipitation increase the chances of the NAC halt. An accurate model suggests the if this trend continues the NAC will shut down entirely within 300 years. NASA 1 (Ocean Circulation Shut Down by Melting Glaciers After Last Ice Age, November 19, /www.giss.nasa.gov) At the end of the last Ice Age 13 to 11.5 thousand years ago, the North Atlantic Deep Water circulation system that drives the Gulf Stream may have shut down because of melting glaciers that added freshwater into the North Atlantic Ocean over several hundred years, NASA and university researchers confirm. Since the Gulf Stream brings warm tropical waters north, Western Europe cooled. The National Science Foundation (NSF) funded study also finds that if a shutdown persisted for a long enough time, the entire Northern Hemisphere would eventually cool. The computer model simulations of ocean and atmosphere processes used in this study imply a similar phenomenon has the potential to occur in the future due to freshwater additions from increased rain and snow caused by global climate change. "For the first time, it is shown that realistic additions of glacial meltwater into the North Atlantic would have shutdown North Atlantic Deep Water production over a period of a few hundred years if the initial ocean circulation was somewhat weaker than that of today," said David Rind, lead author of the study and a senior climate researcher at NASA's Goddard Institute for Space Studies in New York, NY. The study appears in the November 16 issue of Journal of Geophysical Research - Atmospheres. When Rind and his colleagues entered realistic estimates of freshwater from melting glaciers into their model, they found the North Atlantic circulation stopped completely after some 300 years.

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GW  Ice Age (NAC) ( ) There’s a 70 percent chance the NAC shuts down within 200 yrs and a 45 percent chance it happens in this century. Additionally global warming is causing excessive polar precipitation that is melting ice and thereby destabilizing salinity and temperature. This puts us at the brink of an irreversible climate change. Li 5 (Bin, U. of I. research programmer, Global Warming Could Halt Ocean Circulation, Science News) Absent any climate policy, scientists have found a 70 percent chance of shutting down the thermohaline circulation in the North Atlantic Ocean over the next 200 years, with a 45 percent probability of this occurring in this century. The likelihood decreases with mitigation, but even the most rigorous immediate climate policy would still leave a 25 percent chance of a thermohaline collapse. "This is a dangerous, humaninduced climate change," said Michael Schlesinger, a professor of atmospheric sciences at the University of Illinois at Urbana-Champaign. "The shutdown of the thermohaline circulation has been characterized as a highconsequence, low-probability event. Our analysis, including the uncertainties in the problem, indicates it is a high-consequence, high-probability event."Schlesinger will present a talk "Assessing the Risk of a Collapse of the Atlantic Thermohaline Circulation" on Dec. 8 at the United Nations Climate Control Conference in Montreal. He will discuss recent work he and his colleagues performed on simulating and understanding the thermohaline circulation in the North Atlantic Ocean. The thermohaline circulation is driven by differences in seawater density, caused by temperature and salinity. Like a great conveyor belt, the circulation pattern moves warm surface water from the southern hemisphere toward the North Pole. Between Greenland and Norway, the water cools, sinks into the deep ocean, and begins flowing back to the south. "This movement carries a tremendous amount of heat northward, and plays a vital role in maintaining the current climate," Schlesinger said. "If the thermohaline circulation shut down, the southern hemisphere would become warmer and the northern hemisphere would become colder. The heavily populated regions of eastern North America and western Europe would experience a significant shift in climate." Higher temperatures caused by global warming could add fresh water to the northern North Atlantic by increasing the precipitation and by melting nearby sea ice, mountain glaciers and the Greenland ice sheet. This influx of fresh water could reduce the surface salinity and density, leading to a shutdown of the thermohaline circulation. "We already have evidence dating back to 1965 that shows a drop in salinity around the North Atlantic," Schlesinger said. "The change is small, compared to what our model needs to shut down the thermohaline, but we could be standing at the brink of an abrupt and irreversible climate change."

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Scholars

NAC Brink ( ) Our brink is now. Our evidence indicates that the NAC is shifting so as to heavily cool Europe meaning we are bordering an ice age. Lean 4 (Geoffrey, Environment Editor , Global Warming Will Plunge Britain Into New Ice Age 'Within Decades', http://news.independent.co.uk/ ) Britain is likely to be plunged into an ice age within our lifetime by global warming, new research suggests. A study, which is being taken seriously by top government scientists, has uncovered a change "of remarkable amplitude" in the circulation of the waters of the North Atlantic. Similar events in pre-history are known to have caused sudden "flips" of the climate, bringing ice ages to northern Europe within a few decades. The development described as "the largest and most dramatic oceanic change ever measured in the era of modern instruments", by the US Woods Hole Oceanographic Institute, which led the research - threatens to turn off the Gulf Stream, which keeps Europe's weather mild. If that happens, Britain and northern Europe are expected to switch abruptly to the climate of Labrador - which is on the same latitude - bringing a nightmare scenario where farmland turns to tundra and winter temperatures drop below -20C. The much-heralded cold snap predicted for the coming week would seem balmy by comparison. A report by the International Geosphere-Biosphere Programme in Sweden - launched by Nobel prize-winner Professor Paul Crutzen and other top scientists - warned last week that pollution threatened to "trigger changes with catastrophic consequences" like these. Scientists have long expected that global warming could, paradoxically, cause a devastating cooling in Europe by disrupting the Gulf Stream, which brings as much heat to Britain in winter as the sun does: the US National Academy of Sciences has even described such abrupt, dramatic changes as "likely". But until now it has been thought that this would be at least a century away.The new research, by scientists at the Centre for Environment, Fisheries and Aquaculture Science at Lowestoft and Canada's Bedford Institute of Oceanography, as well as Woods Hole, indicates that this may already be beginning to happen. Dr Ruth Curry, the study's lead scientist, says: "This has the potential to change the circulation of the ocean significantly in our lifetime. Northern Europe will likely experience a significant cooling."

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NAC - Most Detailed Studies Prove ( ) The most detailed study yet of ocean flow reveals that there is a dramatic weakening in the NAC due to warming. Even a weakening of this decade over years would have a profound impact. Randerson 6 (James, Science Correspondent for The Guardian, Sea change: why global warming could leave Britain feeling the cold, http://www.guardian.co.uk) Scientists have uncovered more evidence for a dramatic weakening in the vast ocean current that gives Britain its relatively balmy climate by dragging warm water northwards from the tropics. The slowdown, which climate modellers have predicted will follow global warming, has been confirmed by the most detailed study yet of ocean flow in the Atlantic. Most alarmingly, the data reveal that a part of the current, which is usually 60 times more powerful than the Amazon river, came to a temporary halt during November 2004. The nightmare scenario of a shutdown in the meridional ocean current which drives the Gulf stream was dramatically portrayed in The Day After Tomorrow. The climate disaster film had Europe and North America plunged into a new ice age practically overnight. Although no scientist thinks the switch-off could happen that quickly, they do agree that even a weakening of the current over a few decades would have profound consequences. Warm water brought to Europe's shores raises the temperature by as much as 10C in some places and without it the continent would be much colder and drier. Researchers are not sure yet what to make of the 10-day hiatus. "We'd never seen anything like that before and we don't understand it. We didn't know it could happen," said Harry Bryden, at the National Oceanography Centre, in Southampton, who presented the findings to a conference in Birmingham on rapid climate change. Is it the first sign that the current is stuttering to a halt? "I want to know more before I say that," Professor Bryden said. Lloyd Keigwin, a scientist at the Woods Hole Oceanographic Institution, in Massachusetts, in the US, described the temporary shutdown as "the most abrupt change in the whole [climate] record". He added: "It only lasted 10 days. But suppose it lasted 30 or 60 days, when do you ring up the prime minister and say let's start stockpiling fuel? How can we rule out a longer one next year?" Prof Bryden's group stunned climate researchers last year with data suggesting that the flow rate of the Atlantic circulation had dropped by about 6m tonnes of water a second from 1957 to 1998. If the current remained that weak, he predicted, it would lead to a 1C drop in the UK in the next decade. A complete shutdown would lead to a 4C6C cooling over 20 years. The study prompted the UK's Natural Environment Research Council to set up an array of 16 submerged stations spread across the Atlantic, from Florida to north Africa, to measure flow rate and other variables at different depths. Data from these stations confirmed the slowdown in 1998 was not a "freak observation"- although the current does seem to have picked up slightly since.

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NAC Impacts- General ( ) An ocean channel could stop in as little as a decade and an ice age of more than a 1000 years could follow. This threatens our planet with drought, agricultural anomalies, and problems within civilization. Lean 4 (Geoffrey, Environment Editor , Global Warming Will Plunge Britain Into New Ice Age 'Within Decades', http://news.independent.co.uk/ ) Robert Gagosian, the director of Woods Hole, considered one of the world's leading oceanographic institutes, said: "We may be approaching a threshold that would shut down [the Gulf Stream] and cause abrupt climate changes. "Even as the earth as a whole continues to warm gradually, large regions may experience a precipitous and disruptive shift into colder climates." The scientists, who studied the composition of the waters of the Atlantic from Greenland to Tierra del Fuego, found that they have become "very much" saltier in the tropics and subtropics and "very much" fresher towards the poles over the past 50 years. This is alarming because the Gulf Stream is driven by cold, very salty water sinking in the North Atlantic. This pulls warm surface waters northwards, forming the current. The change is described as the "fingerprint" of global warming. As the world heats up, more water evaporates from the tropics and falls as rain in temperate and polar regions, making the warm waters saltier and the cold ones fresher. Melting polar ice adds more fresh water. Ominously, the trend has accelerated since 1990, during which time the 10 hottest years on record have occurred. Many studies have shown that similar changes in the waters of the North Atlantic in geological time have often plunged Europe into an ice age, sometimes bringing the change in as little as a decade. The National Academy of Sciences says that the jump occurs in the same way as "the slowly increasing pressure of a finger eventually flips a switch and turns on a light". Once the switch has occurred the new, hostile climate, lasts for decades at least, and possibly centuries. When the Gulf Stream abruptly turned off about 12,700 years ago, it brought about a 1,300-year cold period, known as the Younger Dryas. This froze Britain in continuous permafrost, drove summer temperatures down to 10C and winter ones to -20C, and brought icebergs as far south as Portugal. Europe could not sustain anything like its present population. Droughts struck across the globe, including in Asia, Africa and the American west, as the disruption of the Gulf Stream affected currents worldwide. Some scientists say that this is the "worst-case scenario" and that the cooling may be less dramatic, with the world's climate "flickering" between colder and warmer states for several decades. But they add that, in practice, this would be almost as catastrophic for agriculture and civilisation.

( ) There are various ways warming could affect the ocean current; this could collapse vital ecosystems, devastate Anarctic fish stocks, disrupt temperatures, kill forests, and ultimately culminate in extinction and an exacerbation of global warming. Hearld 4 (Morning Herald, Sydney (Australia), World's Achilles heels, Oct. 26, 2004, http://www.heatisonline.org) When the world warms, key ecosystems may be tipped out of balance, creating a whole new set of climatic challenges. Ian Sample explains where the dangers lie. Cast an eye over the many forests' worth of scientific literature on global warming, and it becomes clear that working out what a temperature rise of a few degrees will mean for life anywhere on the planet is far from straightforward. Vast icesheets may melt, sea levels will rise and, faced with a new climate, species will have to adapt, move or perish. Yet the precise details of how any of it will happen are unknown. Now it seems the future has become even more uncertain. Climate scientists say they have identified a dozen weak links around the world - regions where global warming could bring about the sudden collapse of vital ecosystems, the effects of which will be felt far afield. An abrupt halt in one ocean current could devastate Antarctic fish stocks; disruption to another could make temperatures in Europe plunge. When rains return to the Sahara, disease and crop damage from pests could soar. Meanwhile, a drier Amazon will trigger dieback of the forests, threatening many species with extinction. Losing the forests will itself exacerbate global warming.

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NAC Impacts – Species Extinction (Plankton) ( ) A change in the NAC would substantially reduce the abundance of plankton. This threatens species extermination in the ocean. Owen in 5 ( James, National Geographic News Correspondent, "Mini Ice Age" May Be Coming Soon, Sea Study Warns, November 30, lexis) Some computer models predict an abrupt stop to the North Atlantic current sometime in the next hundred years. The current is responsible for Europe's relatively mild climate. "Personally I don't think it's going to happen in the next few years, but it's like a nuclear power plant—you've got to look at the risks, even if you don't expect the thing to blow up next week," Quadfasel said. If the current does stop, he says, it would have devastating effects on northwest Europe. The freezing conditions would affect everything from agriculture to energy demand. Marine life could also be seriously affected, according to Andreas Schmittner, assistant professor at Oregon State University's College of Oceanic and Atmospheric Sciences. Stalling of the North Atlantic circulation would halt the flow of nutrients from the deep ocean. "Plankton abundance will strongly decline," Schmittner said. "Since plankton builds the base of the ocean food chain, animals higher up the chain—such as fish, squid and whales—can also be expected to suffer," he said. Such impacts would not be confined to the Atlantic Ocean, he adds. Water that sinks in the North Atlantic resurfaces in the Indian and Pacific Oceans and the seas surrounding Antarctica. "Reduced sinking leads to reduced upwelling of nutrient-rich waters and hence slower growth of algae and other plankton," he said.

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NAC Impacts – Species Extinction (Arctic) ( ) The impacts are happening now. A continual disruption of the North Atlantic Current would completely melt the Arctic ice cap as early as 2020, making polar bears extinct. Leake in 5 (Johnathan, Science Editor for The Sunday, Britain faces big chill as ocean current slows, May 8) Wadhams and his colleagues believe, however, that just such changes could be well under way. They predict that the slowing of the Gulf Stream is likely to be accompanied by other effects, such as the complete summer melting of the Arctic ice cap by as early as 2020 and almost certainly by 2080. This would spell disaster for Arctic wildlife such as the polar bear, which could face extinction. Wadhams’s submarine journeys took him under the North Polar ice cap, using sonar to survey the ice from underneath. He has measured how the ice has become 46% thinner over the past 20 years. The results from these surveys prompted him to focus on a feature called the Odden ice shelf, which should grow out into the Greenland Sea every winter and recede in summer. The growth of this shelf should trigger the annual formation of the sinking water columns. As sea water freezes to form the shelf, the ice crystals expel their salt into the surrounding water, making it heavier than the water below.

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NAC Impacts – Salinity Valves ( ) An influx of freshwater via disturbing the NAC would disrupt salinity valves across the globe. An unbalance in these would rapidly destroy ecosystems. Hearld 4 (Morning Herald, Sydney (Australia), World's Achilles heels, Oct. 26, 2004, http://www.heatisonline.org) In some parts of the world, local geography conspires to pinch the waters between adjacent seas into separate bodies of water. If one is saltier than the other, a flux of salt, nutrients and oxygen can be set up across the gap, producing what scientists refer to as a salinity valve. Probably the most significant salinity valve is the Strait of Gibraltar, acting as a pinch between the Mediterranean and the North Atlantic Ocean. The areas around the valves give rise to unique ecosystems that are highly adapted to local conditions. "Everything is in a balance now - all the ecosystems have adapted to a certain salinity," Schellnhuber says. If conditions around salinity valves change rapidly, he says, those ecosystems may not be able to adapt quickly enough to survive.

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NAC Impacts – Methane Calthrates ( ) An influx of freshwater caused by warming could rupture the methane calthrates in the Siberian permafrost. This would release up t 11 trillion tones of carbon, exacerbating global warming up to 25 percent. Hearld 4 (Morning Herald, Sydney (Australia), World's Achilles heels, Oct. 26, 2004, http://www.heatisonline.org) Deep within the Siberian permafrost and ocean floor sediments lie vast deposits of gas-filled ice called methane clathrates. At Siberian temperatures, or under the weight of icy oceans, the clathrates are stable. But as global warming takes effect, the icy crystals that clutch the gas could rupture, releasing it into the oceans and atmosphere. According to the United States Geological Survey, some 10 trillion to 11 trillion tonnes of carbon are locked up in clathrates in ocean floor deposits, the equivalent of 20 times the known reserves of natural gas. If released into the atmosphere, methane from the clathrates could exacerbate global warming by up to 25 per cent.

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NAC Impacts – Larsen B. Iceshelf ( ) Warming of the ocean could rupture the West Antarctic icesheet. If the Larsen B Iceshelf were to melt, our sea level would rise by more than six metres. This increases the risk of natural disaster for our coastal cities and risks drastic climactic change. Hearld 4 (Morning Herald, Sydney (Australia), World's Achilles heels, Oct. 26, 2004, http://www.heatisonline.org) The giant West Antarctic icesheet won't melt in the near future - the ice is up to a kilometre thick - but two years ago a vast chunk, the Larsen B iceshelf, broke off the eastern side of the Antarctic peninsula and fragmented into icebergs. In just 35 days, about 3250 square kilometres of ice were lost. The shelf is now roughly 40 per cent of the size at which it had previously stabilised. Some predict that the rest of the sheet could feel the force of global warming quickly. Should the entire sheet melt, it is estimated the sea level around the world would rise by more than six metres.

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NAC Impacts – El Nino ( ) The shifting of the NAC would affect the El Nino making the impact on agriculture and food production enormous. This would also incite extreme climactic effects varying in different parts of the world. Hearld 4 (Morning Herald, Sydney (Australia), World's Achilles heels, Oct. 26, 2004, http://www.heatisonline.org) The disruption caused by El Nino is well known, from droughts in Asia and Australia to flooding in regions such as Ecuador and northern Peru. Spanish for "the boy child", the term El Nino was originally used to describe a warm ocean current that arrived around Christmas time. Nowadays it refers to a general warming of the central and Asian Pacific, which causes a major shift in weather patterns. El Ninos are already somewhat erratic, occurring every two to seven years, but some models say global warming may make these events not only more severe but more frequent. The impact on agriculture and food production could be serious. Indonesia, the Philippines, South-East Asia and eastern Australia could face damaging droughts, while the heavy rains and flooding could cause problems for the north-western regions of South America.

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NAC Impacts – Famine ( ) Warming induces changes in the NAC that massively decimate the plankton population. This species is the backbone of the food chain and a reduction in them spells massive famines. Presse 5 (Agence France-Presse, Writer for The Heat is Online; Global Warming: Shutdown Of Atlantic Current Would Ravage Food Stocks, March 31www.heatisonline.org) If the North Atlantic Ocean's circulation system is shut down - an apocalyptic global-warming scenario - the impact on the world's food supplies would be disastrous, a study said last Thursday.The shutdown would cause global stocks of plankton, a vital early link in the food chain, to decline by a fifth while plankton stocks in the North Atlantic itself would shrink by more than half, it said."A massive decline of plankton stocks could have catastrophic effects on fisheries and human food supply in the affected regions," warned the research, authored by Andreas Schmittner of Oregon State University.The circulation system is like a conveyor belt, taking warm water from the Caribbean in the tropical western Atlantic to the cold latitudes of the northeastern Atlantic. There, the warm surface water cools and sinks, gradually getting hauled around back to the southwest, where it warms again and rises to the surface.This movement is vital for northwestern Europe, for the warm water brings the region balmy, wet weather. Without it, Ireland, Britain, parts of France, Belgium, the Netherlands and Germany would be plunged into prolonged, bitter winters.The circulation is also essential for plankton, providing an upwelling of deep-water nutrients on which these tiny creatures feed. In turn, the plankton feed fish and other marine animals, which in turn are harvested by humans.Schmittner, writing in the British weekly science journal Nature, said his computer model of plankton loss was based on a disruption of the circulation system over 500 years, during which the conveyor belt lost more than 80 percent of its power.

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NAC Controls Climate ( ) The North Atlantic current has been called the ‘Achilles’ heel of our climate system. Warming could, at minimum, heavily damage our ecosystem; it will most probably cause flooding and long-term droughts in various regions. Gagosian in 8 (Robert B., President and Director of Woods Hole Oceanographic Institution, May 7, http://www.whoi.edu) Fossil evidence and computer models demonstrate that Earth’s complex and dynamic climate system has more than one mode of operation. Each mode produces different climate patterns. The evidence also shows that Earth’s climate system has sensitive thresholds. Pushed past a threshold, the system can jump quickly from one stable operating mode to a completely different one—“just as the slowly increasing pressure of a finger eventually flips a switch and turns on a light,” the NAS report said. Scientists have so far identified only one viable mechanism to induce large, global, abrupt climate changes: a swift reorganization of the ocean currents circulating around the earth. These currents, collectively known as the Ocean Conveyor, distribute vast quantities of heat around our planet, and thus play a fundamental role in governing Earth’s climate. The oceans also play a pivotal role in the distribution and availability of life-sustaining water throughout our planet. The oceans are, by far, the planet’s largest reservoir of water. Evaporation from the ocean transfers huge amounts of water vapor to the atmosphere, where it travels aloft until it cools, condenses, and eventually precipitates in the form of rain or snow. Changes in ocean circulation or water properties can disrupt this hydrological cycle on a global scale, causing flooding and long-term droughts in various regions. The El Niño phenomenon is but a hint of how oceanic changes can dramatically affect where and how much precipitation falls throughout the planet. Thus, the oceans and the atmosphere constitute intertwined components of Earth’s climate system. But our present knowledge of ocean dynamics does not match our knowledge of atmospheric processes. The oceans’ essential role is too often neglected in our calculations.Does Earth's climate system have an 'Achilles' heel'? Here is a simplified description of some basic ocean-atmosphere dynamics that regulate Earth’s climate: The equatorial sun warms the ocean surface and enhances evaporation in the tropics. This leaves the tropical ocean saltier. The Gulf Stream, a limb of the Ocean Conveyor, carries an enormous volume of heat-laden, salty water up the East Coast of the United States, and then northeast toward Europe. This oceanic heat pump is an important mechanism for reducing equator-to-pole temperature differences. It moderates Earth’s climate, particularly in the North Atlantic region. Conveyor circulation increases the northward transport of warmer waters in the Gulf Stream by about 50 percent. At colder northern latitudes, the ocean releases this heat to the atmosphere—especially in winter when the atmosphere is colder than the ocean and ocean-atmosphere temperature gradients increase. The Conveyor warms North Atlantic regions by as much as 5° Celsius and significantly tempers average winter temperatures. But records of past climates—from a variety of sources such as deep-sea sediments and ice-sheet cores—show that the Conveyor has slowed and shut down several times in the past. This shutdown curtailed heat delivery to the North Atlantic and caused substantial cooling throughout the region. One earth scientist has called the Conveyor “the Achilles’ heel of our climate system.”3

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NAC Controls Ocean Conveyors ( ) The patterns of the NAC are directly affected by global warming. Unfortunately, this current is a ‘deep-limb’ of the ocean conveyor. If warming escalated to a level that’d stop this current, it’d spell cold winters and wide-spread droughts. Gagosian in 8 (Robert B., President and Director of Woods Hole Oceanographic Institution, May 7, http://www.whoi.edu) Solving this puzzle requires an understanding of what launches and drives the Conveyor in the first place. The answer, to a large degree, is salt. For a variety of reasons, North Atlantic waters are relatively salty compared with other parts of the world ocean. Salty water is denser than fresh water. Cold water is denser than warm water. When the warm, salty waters of the North Atlantic release heat to the atmosphere, they become colder and begin to sink. In the seas that ring the northern fringe of the Atlantic—the Labrador, Irminger, and Greenland Seas—the ocean releases large amounts of heat to the atmosphere and then a great volume of cold, salty water sinks to the abyss. This water flows slowly at great depths into the South Atlantic and eventually throughout the world’s oceans. Thus, the North Atlantic is the source of the deep limb of the Ocean Conveyor. The plunge of this great mass of cold, salty water propels the global ocean’s conveyor-like circulation system. It also helps draw warm, salty tropical surface waters northward to replace the sinking waters. This process is called “thermohaline circulation,” from the Greek words “thermos” (heat) and “halos” (salt). If cold, salty North Atlantic waters did not sink, a primary force driving global ocean circulation could slacken and cease. Existing currents could weaken or be redirected. The resulting reorganization of the ocean’s circulation would reconfigure Earth’s climate patterns. Computer models simulating ocean-atmosphere climate dynamics indicate that the North Atlantic region would cool 3° to 5° Celsius if Conveyor circulation were totally disrupted. It would produce winters twice as cold as the worst winters on record in the eastern United States in the past century. In addition, previous Conveyor shutdowns have been linked with widespread droughts throughout the globe.

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NAC Controls Hydrologic Cycle ( ) We win the IL to ocean patterns. Evidence shows that any type of freshwater increase could greatly disrupt the flow of currents, particularly the NAC. Our ev. proves that the NAC has a hydrologic effect on the macro-scale, effecting all of our oceans. MBL 6 (Marine Biological Lab, North Atlantic Ocean freshening could weaken Gulf Stream, August, mongabay.com) A new analysis of 50 years of changes in freshwater inputs to the Arctic Ocean and North Atlantic may help shed light on what's behind the recently observed freshening of the North Atlantic Ocean. In a report, published in the August 25, 2006 issue of the journal, Science, MBL (Marine Biological Laboratory) senior scientist Bruce J. Peterson and his colleagues describe a first-of-its-kind effort to create a big-picture view of hydrologic trends in the Arctic. Their analysis reveals that freshwater increases from Arctic Ocean sources appear to be highly linked to a fresher North Atlantic. The high-latitude freshwater cycle is one of the most sensitive barometers of the impact of changes in climate and broad-scale atmospheric dynamics because of the polar amplification of the global warming signal," says Peterson. "It's easiest to measure these changes in the Arctic and the better we understand this system, the sooner we will know what is happening to the global hydrologic cycle." The multi-disciplinary team of scientists led by Peterson calculated annual and cumulative freshwater input anomalies (deviations from expected levels) from net precipitation on the ocean surface, river discharge, net attrition of glaciers, and Arctic Ocean sea ice melt and export for the latter half of the 20th century. The scientists compared the fluxes to measured rates of freshwater accumulation in the North Atlantic during the same time period. Their analysis showed that increasing river discharge and excess net precipitation on the ocean contributed the most freshwater (~20,000 cubic kilometers) to the Arctic and high-latitude North Atlantic. Sea ice reduction provided another ~15,000 cubic kilometers of freshwater, followed by ~2,000 cubic kilometers from melting glaciers. Together, the sum of anomalous inputs from all of the freshwater sources analyzed matched the amount and rate at which fresh water accumulated in the North Atlantic during much of the period from 1965 through 1995. "This synthesis allows us to judge which freshwater sources are the largest, but more importantly shows how the significance of different sources have changed over the past decades and what has caused the changes," says Peterson. "It prompts us to realize that the relative importance of different sources will change in future decades. Creating a big-picture or synoptic view of the changes in various components of the high-latitude freshwater cycle puts the parts in a perspective where we can judge their individual and collective impact on ocean freshening and circulation." In recent years, much attention has been given to the observed freshening of Arctic Ocean and North Atlantic and the potential impacts it may have on the earth's climate. Scientists contend that a significant increase of freshwater flow to the Arctic Ocean could slow or halt the Atlantic Deep Water formation, a driving factor behind the great "conveyor belt" current that is responsible for redistributing salt and thermal energy around the globe, influencing the planet's climate. One of the potential effects of altered global ocean circulation could be a cooling of Northern Europe within this century

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Gonzaga Debate Institute 2008 Scholars

**********2AC (w/ specific extensions)**********

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Gonzaga Debate Institute 2008 Scholars

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2AC- General Block NOTE: For the 2AC general block it is kept VERY short so as to maximize 2AC offense and time allocation. However, there are very good, strategic cards in the 1AR general extensions section that are not mentioned in the generic 2AC block. It’d be strategic to incorporate some of these cards into your 2AC block after you highlight these down and create more time for yourself. Make yourself familiar with the block, if the 1NC runs a weird module there are good answers in the 1AR section.

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2AC –General Block A. Warming causes ocean-circulation malfunctions, two ways: 1. Warming slows the North Atlantic Current which could change temperatures up to 10 degrees. Pearce in 5 (Fred, Environment and Development Consultant, Failing Ocean Current raises fears of mini ice age, newscientist.com)

The ocean current that gives western Europe its relatively balmy climate is stuttering, raising fears that it might fail entirely and plunge the continent into a mini ice age. The dramatic finding comes from a study of ocean circulation in the North Atlantic, which found a 30% reduction in the warm currents that carry water north from the Gulf Stream. The slow-down, which has long been predicted as a possible consequence of global warming, will give renewed urgency to intergovernmental talks in Montreal, Canada, this week on a successor to the Kyoto Protocol. Harry Bryden at the National Oceanography Centre in Southampton, UK, whose group carried out the analysis, says he is not yet sure if the change is temporary or signals a long-term trend. "We don’t want to say the circulation will shut down," he told New Scientist. "But we are nervous about our findings. They have come as quite a surprise." No one-off The North Atlantic is dominated by the Gulf Stream – currents that bring warm water north from the tropics. At around 40° north – the latitude of Portugal and New York – the current divides. Some water heads southwards in a surface current known as the subtropical gyre, while the rest continues north, leading to warming winds that raise European temperatures by 5°C to 10°C. But when Bryden’s team measured north-south heat flow last year, using a set of instruments strung across the Atlantic from the Canary Islands to the Bahamas, they found that the division of the waters appeared to have changed since previous surveys in 1957, 1981 and 1992. From the amount of water in the subtropical gyre and the flow southwards at depth, they calculate that the quantity of warm water flowing north had fallen by around 30%. When Bryden added previously unanalysed data – collected in the same region by the US government’s National Oceanic and Atmospheric Administration – he found a similar pattern. This suggests that his 2004 measurements are not a one-off, and that most of the slow-down happened between 1992 and 1998. The changes are too big to be explained by chance, co-author Stuart Cunningham told New Scientist from a research ship off the Canary Islands, where he is collecting more data. "We think the findings are robust."

2. GW will also shift the Atlantic circumpolar current causing more rainfall over the poles. Hearld 4 (Morning Herald, Sydney (Australia), World's Achilles heels, Oct. 26, 2004, http://www.heatisonline.org) Some scientists believe the Atlantic circumpolar current is the most significant on the planet. It swirls 140 million cubic metres of water around Antarctica every second, mixing water from the Pacific, Atlantic and Indian oceans as it goes. The current taps into another circulation that causes cold surface water to sink while warmer water rises, bringing with it vital nutrients from dead plankton and other marine life on the ocean floor. Global warming is expected to produce more rainfall over the poles, which could slow the rise of nutrients for dispersal by the Atlantic circumpolar current. "For marine life, any change in the currents is extremely important," Schellnhuber says.

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2AC –General (2/3) B. An NAC halt means serious business. It could last as long as 1000 years which threatens our planet with drought, agricultural anomalies, and civil strife. Lean 4 (Geoffrey, Environment Editor , Global Warming Will Plunge Britain Into New Ice Age 'Within Decades', http://news.independent.co.uk/ ) Robert Gagosian, the director of Woods Hole, considered one of the world's leading oceanographic institutes, said: "We may be approaching a threshold that would shut down [the Gulf Stream] and cause abrupt climate changes. "Even as the earth as a whole continues to warm gradually, large regions may experience a precipitous and disruptive shift into colder climates." The scientists, who studied the composition of the waters of the Atlantic from Greenland to Tierra del Fuego, found that they have become "very much" saltier in the tropics and subtropics and "very much" fresher towards the poles over the past 50 years. This is alarming because the Gulf Stream is driven by cold, very salty water sinking in the North Atlantic. This pulls warm surface waters northwards, forming the current. The change is described as the "fingerprint" of global warming. As the world heats up, more water evaporates from the tropics and falls as rain in temperate and polar regions, making the warm waters saltier and the cold ones fresher. Melting polar ice adds more fresh water. Ominously, the trend has accelerated since 1990, during which time the 10 hottest years on record have occurred. Many studies have shown that similar changes in the waters of the North Atlantic in geological time have often plunged Europe into an ice age, sometimes bringing the change in as little as a decade. The National Academy of Sciences says that the jump occurs in the same way as "the slowly increasing pressure of a finger eventually flips a switch and turns on a light". Once the switch has occurred the new, hostile climate, lasts for decades at least, and possibly centuries. When the Gulf Stream abruptly turned off about 12,700 years ago, it brought about a 1,300-year cold period, known as the Younger Dryas. This froze Britain in continuous permafrost, drove summer temperatures down to 10C and winter ones to -20C, and brought icebergs as far south as Portugal. Europe could not sustain anything like its present population. Droughts struck across the globe, including in Asia, Africa and the American west, as the disruption of the Gulf Stream affected currents worldwide. Some scientists say that this is the "worst-case scenario" and that the cooling may be less dramatic, with the world's climate "flickering" between colder and warmer states for several decades. But they add that, in practice, this would be almost as catastrophic for agriculture and civilisation.

C. We access a better timeframe. NAC is slowing now, more freshwater could stop its current. Lean 4 (Geoffrey, Environment Editor , Global Warming Will Plunge Britain Into New Ice Age 'Within Decades', http://news.independent.co.uk/ ) Britain is likely to be plunged into an ice age within our lifetime by global warming, new research suggests. A study, which is being taken seriously by top government scientists, has uncovered a change "of remarkable amplitude" in the circulation of the waters of the North Atlantic. Similar events in pre-history are known to have caused sudden "flips" of the climate, bringing ice ages to northern Europe within a few decades. The development described as "the largest and most dramatic oceanic change ever measured in the era of modern instruments", by the US Woods Hole Oceanographic Institute, which led the research - threatens to turn off the Gulf Stream, which keeps Europe's weather mild. If that happens, Britain and northern Europe are expected to switch abruptly to the climate of Labrador - which is on the same latitude - bringing a nightmare scenario where farmland turns to tundra and winter temperatures drop below -20C. The much-heralded cold snap predicted for the coming week would seem balmy by comparison. A report by the International Geosphere-Biosphere Programme in Sweden - launched by Nobel prize-winner Professor Paul Crutzen and other top scientists - warned last week that pollution threatened to "trigger changes with catastrophic consequences" like these. Scientists have long expected that global warming could, paradoxically, cause a devastating cooling in Europe by disrupting the Gulf Stream, which brings as much heat to Britain in winter as the sun does: the US National Academy of Sciences has even described such abrupt, dramatic changes as "likely". But until now it has been thought that this would be at least a century away.The new research, by scientists at the Centre for Environment, Fisheries and Aquaculture Science at Lowestoft and Canada's Bedford Institute of Oceanography, as well as Woods Hole, indicates that this may already be beginning to happen. Dr Ruth Curry, the study's lead scientist, says: "This has the potential to change the circulation of the ocean significantly in our lifetime. Northern Europe will likely experience a significant cooling."

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2AC –General (3/3) D. Even if we adopted their crazy theory, GW could not stop an ice age. Lovell in 6 (Jeremy, Writer for Wild Singapore, Key Warming Ocean Current Slowing Down, www.wildsingapore.com) The Atlantic Conveyor, a life-giving ocean current that keeps northern Europe warm, is slowing down, scientists said on Wednesday. If the 30 percent slowdown seen over the past 12 years is not just a blip, temperatures in northern Europe could drop significantly, despite global warming, they added. Scientists have long forecast that the Atlantic Conveyor that carries warm surface water north and cold deep water back to the equator could break down because of global warming. According to the theory, rising air temperatures cause ice caps to melt, making the water less salty and therefore less dense so it can't sink and flow back south. The scientists on Wednesday said this was the first time that observations had put flesh on the bones of the theory. "This is the first time we have observed a change in the current on a human timescale," oceanographer Harry Bryden said, noting that it had completely shut down during the ice ages. But he said the latest figures were far from proving a trend and that constant and long-term monitoring was needed. "It is like a radiator heating the atmosphere and is too important to leave to periodic observations," Bryden told a news conference to flesh out a paper he co-authored in Nature science journal.

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2AC - Volcanoes Turn A. Warming causes volcanic eruptions, two ways: 1. Warming-induced ice-melt increases pressure on earth’s crust, spurring volcanic activity LiveScience.com, ‘07 (Global Warming Might Spur Earthquakes and Volcanoes, Aug 30, http://www.livescience.com/environment/070830_gw_quakes.html) Earthquakes, volcanic eruptions, tsunamis and landslides are some of the additional catastrophes that climate change and its rising sea levels and melting glaciers could bring, a geologist says. The impact of human-induced global warming on Earth's ice and oceans is already noticeable: Greenland's glaciers are melting at an increasing rate, and sea level rose by a little more than half a foot (0.17 meters) globally in the 20th century, according to the Intergovernmental Panel on Climate Change. With these trends in ice cover and sea level only expected to continue and likely worsen if atmospheric carbon dioxide levels continue to rise, they could alter the stresses and forces fighting for balance in the ground under our feet—changes that are well-documented in studies of past climate change, but which are just beginning to be studied as possible consequences of the current state of global warming. "Although they've described it in the past, nobody's thought about it in terms of future effects of climate change," said Bill McGuire of the University College London's Hazard Research Center. McGuire's speculations of increased geological activity have not yet been published in a journal, but he has written an article about them published in the Guardian Unlimited. Rebounding crust One particular feature that can change the balance of forces in Earth's crust is ice, in the form of glaciers and ice sheets that cover much of the area around Earth's poles plus mountains at all latitudes. The weight of ice depresses the crust on which it sits. As the ice melts, the crust below no longer has anything sitting on top of it, and so can rebound fairly rapidly (by geological standards). (This rebounding is actually occurring now as a result of the end of the last Ice Age: The retreat of massive ice sheets from the northern United States and Canada has allowed the crust in these areas to bounce back.) Areas of rebounding crust could change the stresses acting on earthquake faults and volcanoes in the crust. "In places like Iceland, for example, where you have the Eyjafjallajökull ice sheet, which wouldn't survive [global warming], and you've got lots of volcanoes under that, the unloading effect can trigger eruptions," McGuire said.

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2AC Volcanoes (2/3) 2. Ice melt causes sea-level rise; compression of magma veins triggers volcanic eruptions. Pavlof and Mediterranean studies prove. LiveScience.com, ‘07 (Global Warming Might Spur Earthquakes and Volcanoes, Aug 30, http://www.livescience.com/environment/070830_gw_quakes.html) Water pressure Ice melt can have an added consequence because all that melted ice has to go somewhere—namely, the ocean. And ice melt won't be the only factor changing sea levels: as ocean temperatures rise, the water itself expands (a process called thermal expansion). As all that extra water piles up, it could apply pressure to faults near coastlines. "The added load of the water bends the crust, and that means that you tend to get tensional conditions in the upper part of the crust and compressional a bit lower down, just as if you bend a plank of wood or something," McGuire explained. These compressional forces could push out any magma lying around underneath a volcano, triggering an eruption. (This mechanism is actually believed to be the cause of the seasonal eruptions of Alaska's Pavlof volcano, which erupts every winter when sea levels are higher.) McGuire conducted a study that was published in the journal Nature in 1997 that looked at the connection between the change in the rate of sea level rise and volcanic activity in the Mediterranean for the past 80,000 years and found that when sea level rose quickly, more volcanic eruptions occurred, increasing by a whopping 300 percent. If today's worst-case global warming scenarios of catastrophic melting of glaciers and ice sheets come to pass, sea levels could rise rapidly, wreaking all sorts of geological havoc "comparable with the most rapid increases in sea level that we've seen in the last 15,000 years," McGuire said.

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2AC Volcanoes (3/3) B. Super volcano eruption would devastate world agriculture, cause perpetual winter, and species extinction. Nasa.gov, ‘98 (“volcanoes and C=Global Climate change, Earth science enterprise Series, May 1998, http://www.gsfc.nasa.gov/gsfc/service/gallery/fact_sheets/earthsci/eos/volcanoes.pdf) The eruption of a super volcano "sooner or later" will chill the planet and threaten human civilization, British scientists warned Tuesday. And now the bad news: There's not much anyone can do about it. Several volcanoes around the world are capable of gigantic eruptions unlike anything witnessed in recorded history, based on geologic evidence of past events, the scientists said. Such eruptions would dwarf those of Mount St. Helens, Krakatoa, Pinatubo and anything else going back dozens of millennia. "Super eruptions are up to hundreds of times larger than these," said Stephen Self of Britain's Open University. "An area the size of North America can be devastated, and pronounced deterioration of global climate would be expected for a few years following the eruption," Self said. "They could result in the devastation of world agriculture, severe disruption of food supplies, and mass starvation. These effects could be sufficiently severe to threaten the fabric of civilization." Self and his colleagues at the Geological Society of London presented their report to the British government's Natural Hazard Working Group. "Although very rare, these events are inevitable, and at some point in the future humans will be faced with dealing with and surviving a super eruption," Stephen Sparks of the University of Bristol told LiveScience in advance of Tuesday's announcement. Supporting evidence The warning is not new. Geologists in the United States detailed a similar scenario in 2001, when they found evidence suggesting volcanic activity in Yellowstone National Park will eventually lead to a colossal eruption. Half the United States will be covered in ash up to 3 feet (1 meter) deep, according to a study published in the journal Earth and Planetary Science Letters. Explosions of this magnitude "happen about every 600,000 years at Yellowstone," says Chuck Wicks of the U.S. Geological Survey, who has studied the possibilities in separate work. "And it's been about 620,000 years since the last super explosive eruption there." Past volcanic catastrophes at Yellowstone and elsewhere remain evident as giant collapsed basins called calderas. A super eruption is a scaled up version of a typical volcanic outburst, Sparks explained. Each is caused by a rising and growing chamber of hot molten rock known as magma. "In super eruptions the magma chamber is huge," Sparks said. The eruption is rapid, occurring in a matter of days. "When the

magma erupts the overlying rocks collapse into the chamber, which has reduced its pressure due to the eruption. The collapse forms the huge crater." The eruption pumps dust and chemicals into the atmosphere for years, screening the Sun and cooling the planet. Earth is plunged into a perpetual winter, some models predict, causing many plant and animal species to disappear forever. "The whole of a continent might be covered by ash, which might take many years — possibly decades — to erode away and for vegetation to recover," Sparks said. Yellowstone may be winding down geologically, experts say. But they believe it harbors at least one final punch. Globally, there are still plenty of possibilities for super volcano eruptions, even as Earth quiets down over the long haul of its 4.5-billion-year existence. "The earth is of course losing energy, but at a very slow rate, and the effects are only really noticeable over billions rather than millions of years," Sparks said.

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Ext. SO2 cools ( ) Volcanic eruptions cool the globe—sulfur dioxide gas converts to aerosols which deflect sunlight. Mount Pinatubo proves. Moore, scientist in the Climate and Air Program, Environmental Defense Fund, ‘07 (Lisa, “Do Volcanoes Cause Global Warming?”, May 21 2007, http://environmentaldefenseblogs.org/climate411/2007/05/21/volcanoes/) As you can see, CO2 is steadily increasing. The arrows show the five largest volcanic eruptions during that time period. They didn't leave much of a mark, did they? We can see evidence of volcanic eruptions in another dataset: temperatures. But the effect of eruptions is to cool the globe, rather than heat it! Huge volcanic eruptions can shoot significant amounts of sulfur dioxide into the stratosphere. This gas is converted to sulfate aerosols, which reflect sunlight and have a cooling effect. Because of the way the atmosphere circulates, tropical volcanoes have a stronger cooling effect than mid- and high-latitude eruptions of the same magnitude. The graph below is Figure 1 in Chapter 8 [PDF] of the latest IPCC report. The black line shows temperatures, the yellow lines show results from 14 different models, and the red line is the average of all the simulations. As you can see, the four biggest tropical eruptions over the past century had slight cooling effects. The Mount Pinatubo eruption was especially interesting because it provided a great early test for climate models. After Pinatubo exploded, scientists entered emission measurements into their climate models and compared the results with actual observations. The next figure shows that comparison (a larger version is available here). The solid line shows temperature measurements and the dashed lines show model simulations. Two things really jump out of this graph. First, the reflective aerosols from the eruption had a substantial cooling effect. And second, the climate model did a pretty darn good job of predicting the resulting climate change.

( ) Volcanic gases deflect energy from the sun, cooling the earth; “year without summer” proves Nasa.gov, ‘98 (“volcanoes and C=Global Climate chnage, Earth science enterprice Series, May 1998, http://www.gsfc.nasa.gov/gsfc/service/gallery/fact_sheets/earthsci/eos/volcanoes.pdf) Volcanic gases are thought to be responsible for the global cooling that has sometimes been observed for a few years after a major eruption. The amount and global extent of the cooling depend on the force of the eruption, the amount of particular gases emitted, and, perhaps, on the location of the volcano with respect to the world's global atmospheric circulation patterns. When large masses of gases from the eruption reach the stratosphere, they can produce a large, widespread cooling effect. As a prime example, the effects of Mount Pinatubo, which erupted in June 1991, may have lasted a few years, serving to offset temporarily the predicted greenhouse warming effect. Figure 1 illustrates that as volcanoes erupt, they blast huge clouds into the atmosphere. These clouds are made up of particles and gases, including sulfur dioxide. Millions of tons of sulfur dioxide gas can reach the stratosphere from a major eruption. There, the sulfur dioxide converts to tiny persistent sulfuric acid (sulfate) particles, referred to as aerosols. These sulfate particles reflect energy coming from sun, thereby decreasing the amount of sunlight reaching and heating the Earth's surface. Short term global cooling often has been linked with some major volcanic eruptions. The year 1816 has been referred to as “the year without a summer.” It was a time of significant weather-related disruption in New England and in Western Europe with killing summer frosts in the United States and Canada. These strange phenomena were attributed to a major eruption of the Tambora volcano in 1815 in Indonesia. The volcano threw sulfur dioxide gas into the stratosphere, and the aerosol layer that formed led to brilliant sunsets seen around the world for several years. But, not all volcanic eruptions, not even all large volcanic eruptions, produce global-scale cooling. Mount Agung in 1963 apparently caused a considerable decrease in temperatures around much of the world, whereas El Chichón in 1982 seemed to have little effect, perhaps because of its different location or because of the El Niño that occurred the same year. (See NASA Facts NF211.) El Niño is a Pacific Ocean phenomenon, but it causes worldwide weather variations that may have acted to cancel out the effect of the El Chichón eruption.

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Ext. SO2 cools ( ) Volcanic ash would shield the sun for several years; future eruptions would mask global warming Gibbons, prof of ecology, U of Georgia, ‘08 (Whit, “COULD VOLCANOES SAVE US FROM GLOBAL WARMING?”, Feb 17 2008) Believing as I do that global warming is a reality, I think we will find out what the consequences of melting polar ice caps and shorter winters really are. But that outcome might be delayed by a natural event: a volcanic eruption of a magnitude that actually affects the world's climate. All human influences on global warming could be masked temporarily by the eruption of a major volcano. Global cooling from a volcano can occur as a result of sun-shielding by airborne products from the eruptions. The ash, most of which settles to earth within a few weeks, is not the volcanic product that blocks the sun's rays for a long period. Sun-shielding is caused by tiny droplets of sulfuric acid that can remain in the stratosphere for up to three years. Volcanic activity at the earth's surface has been around since the crust cooled, and it will continue for several billion years. Many people remember the eruption of Mount Saint Helens in 1980, the most destructive volcanic eruption to date in the United States. Other volcanoes have also made lasting impressions, such as Vesuvius, which resulted in lots of mummified bodies in the town of Pompeii. Unzen in Japan and Mount Pinatubo in the Philippines became revitalized in the early 1990s and garnered worldwide attention. Mount Pinatubo is calculated to have spewed out more than 20 million tons of sulfur dioxide that reached the stratosphere. Global cooling effects from major volcanic eruptions of that magnitude have the potential to confound interpretations of already controversial studies to determine if global warming from human activities is a phenomenon to be apprehensive about. When Krakatau (sometimes called Krakatoa) erupted in 1833 it had a major influence on the environment. If something of that magnitude occurred today, most news stories about human-caused atmospheric change would seem trivial. Because the earth's temperature would change dramatically, the finger-pointing about global warming would become completely irresolvable. When Krakatau blew its lid, an eighteen-square-mile volcanic island located between Australia and Borneo disappeared. The sound of the Krakatau eruption was reportedly heard more than 3,000 miles away. Tidal waves were created in southeast Asia, and at least 36,000 people perished in coastal cities. Rocks and ash were reportedly thrown more than 15 miles high. The ash cloud was so thick that villages 150 miles away were in total darkness for days.

Though not as famous as Krakatau's performance, Tamburo's eruption produced even more dramatic environmental results. In 1815 that Indonesian volcano spewed enough ash and aerosols into the atmosphere to create a cold snap. In Europe, 1815 became known as "the year without summer." A volcanic eruption the magnitude of Krakatau's or Tamburo's would lay all arguments about global climate change to rest for awhile. And we can certainly expect more environmental drama from volcanoes in the future, although no one knows when and where. The results of such an eruption would be spectacular and far reaching. I kind of look forward to it.

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Ext. SO2 cools ( ) Volcanic eruptions result in a much-needed global cooling, the temperature decline can be seen for several years after an eruption Nytimes.com, ‘91 (“Volcano's Eruption in Philippines May Counteract Global Warming” June 21 1991) A global warming trend that began in the 1980's and has continued into 1991 could be offset over the next few years by atmospheric cooling caused by the eruption this month of the Mount Pinatubo volcano in the Philippines, scientists say. The major factor at work in the climatic effect is not the familiar dust cloud, but a chemical reaction. Volcanic eruptions spew out vast quantities of sulfur dioxide gas that later combine with water to form tiny supercooled droplets. The droplets constitute a long-lasting global haze that reflects and scatters sunlight, causing the earth to cool. This last occurred in 1982, when haze from the eruption of El Chichon volcano in Mexico depressed global temperatures for about four years before a warming trend that began around 1980 resumed in late 1986. Decline Seen for Several Years The cloud of sulfur dioxide from the June 15 eruption in the Philippines is roughly twice as large as that of El Chichon, scientists have now determined, making Mount Pinatubo perhaps the biggest eruption of the 20th century. Experts believe that the haze it is producing could lower the average global temperature by more than half a degree Fahrenheit for three or four years, countering the global warming. A number of scientists expect the warming of the last few years to resume after the mid-1990's, once the haze disperses. An average global cooling of half a degree would scarcely be noticed by people on the street. But it is important in the context of the global warming problem, and it could reduce, for a time, the odds in favor of milder winters and hotter summers. Many scientists expect that by the end of the next century the earth's temperature will rise 2 to 9 degrees above a global average that is now just shy of 60 degrees. A warming in the high end of that range would bring catastrophic disruptions in climate, ecology and agriculture.

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2AC - Polar Precipitation Turn A. Warming will increase polar precipitation. World Climate Report 06 [“The Arctic Precipitation Conundrum,” November 6, http://www.worldclimatereport.com/index.php/2006/11/06/the-arctic-precipitation-conundrum/] In a recent issue of Geophysical Research Letters, a consortium of scientists from the Universities of New Hampshire and Delaware reported on their research that engaged the idea that “both theoretical arguments and models suggest that net high-latitude precipitation increases in proportion to increases in mean hemispheric temperature.” This idea stems from the basic atmospheric principle that warm air stores more water vapor than cold air. Citing the Arctic Climate Impact Assessment (2005), the authors state that in regard to the Arctic, “Warming is predicted to enhance atmospheric moisture storage resulting in increased net precipitation, since precipitation increases will likely exceed evaporative losses.” Whether or not the actual data support these ideas is important, as previous research has documented significant increases in river discharge across Eurasia since the 1930s (Peterson et al. 2002). This takes us back to alteration of the oceanic thermohaline circulation. As the authors state, previous work has determined that “increased precipitation is the most plausible source for the observed discharge trend.”

B. Increasing polar precipitation as a result of warming will lead to an ice age. Novak [Gary, “The Future, as an Ice Age Begins,” http://nov55.com/fure.html] At this time, winters are getting milder in North America due to ice melting around the North Pole. There is also an increase in rainfall due to warmer oceans evaporating more moisture. With growing seasons getting longer, this all adds up to good agriculture. The corn belt has moved farther west into the plains over the past 25 years producing record corn and soybean harvests. This trend should continue for a century or two, until a temperature reversal occurs. It may be a volcano which causes the temperature reversal, because there is no apparent reason why a cool-down would begin otherwise. The reversal occurs when snow and ice increase in northern areas reflecting away more radiation from the sun. Precipitation stays high, because oceans stay warm at the beginning of the reversal. The precipitation creates more snow when the reversal begins, and since more snow reflects away more sunlight, the cool-down is very rapid and irreversible.

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Ext. GW  PP Warming will increase polar precipitation. World Climate Report 06 [“The Arctic Precipitation Conundrum,” November 6, http://www.worldclimatereport.com/index.php/2006/11/06/the-arctic-precipitation-conundrum/] In a recent issue of Geophysical Research Letters, a consortium of scientists from the Universities of New Hampshire and Delaware reported on their research that engaged the idea that “both theoretical arguments and models suggest that net high-latitude precipitation increases in proportion to increases in mean hemispheric temperature.” This idea stems from the basic atmospheric principle that warm air stores more water vapor than cold air. Citing the Arctic Climate Impact Assessment (2005), the authors state that in regard to the Arctic, “Warming is predicted to enhance atmospheric moisture storage resulting in increased net precipitation, since precipitation increases will likely exceed evaporative losses.” Whether or not the actual data support these ideas is important, as previous research has documented significant increases in river discharge across Eurasia since the 1930s (Peterson et al. 2002). This takes us back to alteration of the oceanic thermohaline circulation. As the authors state, previous work has determined that “increased precipitation is the most plausible source for the observed discharge trend.”

Warming will result in increased Antarctic precipitation. Markus 05+ [Thorsten, from NASA’s Goddard Space Flight Center, Earth and Sky, “Global Warming Might Leave Some Places Colder,” http://www.earthsky.org/article/thorsten-markus-interview] Frank: How is warmer air increasing the volume of sea ice in the Antarctic’s Southern Ocean? It seems very counterintuitive. Markus: Yes, it does indeed. The main reason, and this is what our study has shown, is that with warmer air temperatures, the air is able to hold more moisture, which results in increased precipitation. The precipitation adds a layer of snow on top of the sea ice. With this snow layer on top of the sea ice, part of the sea ice is submerged below the sea level, and then the snow becomes ice and it makes thicker ice.

Atmospheric temperature increases result in Antarctic precipitation. Markus 05+ [Thorsten, from NASA’s Goddard Space Flight Center, Earth and Sky, “Global Warming Might Leave Some Places Colder,” http://www.earthsky.org/article/thorsten-markus-interview] Markus: This is what studies suggest, if temperatures are increasing and precipitation with it is increasing as well. Very recent studies by other scientists have shown this correlation between warmer air temperatures and precipitation in the southern hemisphere. So, if this trend exists, we will likely see a further increase in the sea ice cover in the Antarctic.

Antarctic precipitation has been increasing as regional warming increases. EPA 07 [Climate Change – Health and Environmental Effects, “Polar Regions,” December 17, http://www.epa.gov/climatechange/effects/polarregions.html] Over the past half-century, there has been a marked warming trend in the Antarctic Peninsula. Much of the rest of Antarctica has cooled during the last 30 years, due to ozone depletion and other factors, but this trend is likely to reverse. Surface waters of the Southern Ocean surrounding Antarctica have warmed and become less saline, and precipitation in this region has increased (IPCC, 2007a).

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Ext. Ice Age = Inevitable An ice age is inevitable in the very near future – maybe 2013. Lewis 08 [J.C., Dr., The Observer, “Next Ice Age Could be Closing In,” June 26] It is known that at least one of the recent ice ages was generated by an open (ice-free) Arctic Ocean. Because of lag time between generating greenhouse gases and their effects, we cannot reverse global warming in time to ward off this next ice age. It is estimated now that the Arctic Ocean will be ice free in September (month for warmest ocean water) by the year 2013. The irony of the recent intense global warming is that it is accelerating the advent of the next ice age. It could begin in five years; maybe less.

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Polar Precipitation = Inevitable Arctic precipitation is projected to increase for the next century. Hassol 04 [Susan, Arctic Climate Impact Association, Impacts of a Warming Arctic: Arctic Climate Impact Assessment, www.acia.uaf.edu] Increasing Precipitation Arctic precipitation has increased by about 8% on average over the past century. Much of the increase has come as rain, with the largest increases in autumn and winter. Greater increases are projected for the next 100 years.

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2AC – Glacial Melting Turn A. Warming causes glacial melting, this results in cooling in two ways: 1. Melting causes density changes in the NAC. Davidson 04 (“How Global Warming Can Chill the Planet” By Sarah Davidson, LiveScience Staff Writer posted: 17 December, 2004 7:00 a.m. ET Live Science http://www.livescience.com/environment/041217_sealevel_rise.html accessed June 29, 2008) Scientists hope new evidence of an ancient rise in sea level from a fresh water flood will tell them how global warming can lead to global cooling. A global cooling event was caused by global warming? Sounds strange. But that is exactly what scientists say happened. The Earth was emerging from an ice age 8,200 years ago. Seas were warming and life was heating up. Then quite abruptly and for a relatively short period of time -- about 100 years -- the entire globe chilled down again, by almost 10.8 degrees Fahrenheit (6 Centigrade). One widely held theory for the chill was the sudden release of a substantial amount of fresh water into the northern Atlantic. A lake twice the size of the Caspian Sea broke through an ice sheet that contained it over current day Minnesota and Canada, the evidence shows. It poured its fresh water into the salty Atlantic and changed the density of the ocean water. The oceans work on a sort of conveyor belt method to circulate cold and warm waters, thereby helping control cold, moderate, and warm areas of the globe. (Earth's climate is only partly affected by land temperatures and sunlight. Oceans, which store vast amounts of energy and are slow to warm up and cool down, contribute greatly to climate.) But what happens if that conveyor belt stops or slows down? Cold, fresh water sinks, and warm salty water rises. The influx of fresh water into the Hudson Bay from Lake Agassiz provided a barrier against the warm, salty water struggling to move north on the conveyor belt. This effectively shut down the circulation of warm water in the Northern Atlantic. With warm waters unable to move as far north the world became cooler. The amount of water Lake Agassiz dumped into the ocean is equivalent to how much the seas rose. Knowing these amounts will tell scientists how much fresh water could create this type of climate change nowadays, were a bunch of it to suddenly find its way into the ocean. The oceans were able to find their balance relatively quickly in that ancient event, and the effects wore off in about a century, but a century of that kind of change today would create widespread havoc. "There is nothing like Lake Agassiz today, but there are things that could have a comparable effect," said Torbjorn E. Tornqvist, an geologist at the University of Illinois at Chicago. "Places like the Greenland ice sheet are very sensitive to warming and a lot of fresh water could enter the northern oceans and mess up circulation." Scenarios such as this are exactly why Törnqvist says investigations into past climate are vital to understanding current and future climate. "What if patterns of precipitation change from global warming? Having more precipitation in one place than in another could freshen ocean waters and play a role in climate cooling," Tornqvist told LiveScience.

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2AC – Glacial Melting Turn 2. Stops the gulf stream. Poling 99. Poling, “Global warming can cause global cooling”. http://www.dinosauria.com/jdp/news/freeze.html accessed June 29, 2008) Scientists announced in the July 21, 1999, edition of the journal Nature findings that suggest that global warming can sometimes lead to cold weather or even a worldwide freeze. Scientists have long known that a severe cold spell occurred after the end of the Pleistocene glaciation, approximately 8,200 years ago. The cause, however, has been a mystery. The authors of the Nature article write that the centuries long cold spell might have been caused by meltwater from the disappearing glaciers, cooling the North Atlantic. The Laurentide Ice Sheet covered parts of North America with ice up to two miles thick for more than a million years. When the Earth began to warm 10,000 years ago, it retreated back toward the poles. The ice sheet left in its wake at least two lakes containing more water than the Great Lakes combined. In the Hudson Bay, ice held the water in place like a plug in a bathtub. When the plug finally melted, trillions of gallons gushed into the Labrador Sea, flowing out at 100 times the rate water leaves the Mississippi. The conclusions of the authors are the result of a study by University of Colorado and Canadian researchers who examined evidence of this huge flood in the Hudson Bay region of Quebec and Ontario. Independent research showed that global temperatures dropped significantly within several hundred years of the flood. Until this study, nobody could pinpoint if these two events were connected, said the study's lead author, University of Colorado geologist Don Barber. The scientists used radiocarbon dating of clams in the flood sediment, and other evidence, to correlate the two events. The Atlantic Gulf Stream normally acts like a conveyor belt to deliver warm tropical water to temperate regions. By adding so much cold fresh water in such a short time, the flood shut down the Gulf Stream, said Richard Alley, a climate expert at Penn State University. Temperatures in Greenland and Europe dropped by 6 to 15 degrees for at least 200 years, according to ice core data. The authors conclusions demonstrate how global warming can, paradoxically, provoke a global freeze. If a modern glacier such as the Greenland Ice Sheet melts as a result of rising temperatures in the next century, it could trigger a similar flood and climate fluctuation, the researchers said.

B. We do not need to win a halt of a current. Warming induces a change in glacial movement, causing cooling. Bischof 02 (Jens Bischof is author of Ice Drift, Ocean Circulation And Climate Change and is a research assistant professor in Old Dominion’s Department of Ocean, Earth and Atmospheric Sciences. “Ice In The Greenhouse:Earth May Be Cooling, Not Warming” from Quest January 2002 • Volume 5 Issue 1 http://www.odu.edu/ao/instadv/quest/greenhouse.html accessed June 29, 2008) Global cooling brought on by ice drift, however, does not require an external motor, such as the periodic variation in the Earth’s orbit that brings it closer to or farther away from the Sun, or a slight change in the tilt of the Earth’s axis, also periodic. Rather, a mere change of the ice-drift direction in the Arctic could set cooling on its way, possibly even on a global scale. The geologic record is certainly clear: The climate pendulum has repeatedly swung between a relatively warmer worldas we experience today, and glacial climates during which much of Earth was submerged under thick sheets of ice.

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Ext. Ice Melt  IA Ice rafting from melting shifts ocean currents and leads to cooling Bischof 02 (Jens Bischof is author of Ice Drift, Ocean Circulation And Climate Change and is a research assistant professor in Old Dominion’s Department of Ocean, Earth and Atmospheric Sciences. “Ice In The Greenhouse:Earth May Be Cooling, Not Warming” from Quest January 2002 • Volume 5 Issue 1 http://www.odu.edu/ao/instadv/quest/greenhouse.html accessed June 29, 2008) Nevertheless, Earth is overdue for a cold snap. Close examination of the way ice is presently traveling in ocean water, from frigid to warmer regions of the globe, suggests that the mechanisms for widespread planetary cooling may once again be engaging. Ice rafting is a simple idea: particles such as stones, pebbles and fine grains become embedded in ice. As that ice drifts, it melts, depositing those particles in oceanic sediments, leaving a “drift track” indicative of its source. Geologists are then able to reconstruct past ice-drift directions by finding a method by which particles can be connected to a specific point of origin. The process of ice rafting is intimately connected to temperature changes on global and regional scales. The physical movement of excessive amounts of ice from polar regions to lower latitudes by shifting ocean currents can lead to substantially lower temperatures. If, for example, the air pressure distribution over the Arctic Ocean was such that winds blew from the Bering Strait across the North Pole toward Fram Strait, then massive amounts of pack ice would be moved into the Norwegian Greenland Sea. In the winter, this process would continuously produce additional sea ice in the open leads created by offshore winds in the Bering Strait region, setting in motion a veritable “ice machine.” The regional extent of ice and snow cover in the Greenland Sea would increase, cooling the region, and boosting the albedo, or amount of solar radiation reflected back into space, further amplifying cooling. Depending on the strength and duration, this process could lead to an episode of relatively cold climate over the North Atlantic region, perhaps lasting from a few years up to decades. But if it were sufficiently strong and durable, it could set the stage for global climate to return to full glaciation.

Iceberg melt lowers water temperature, parallel to historical warming to extremely cold climatic cycles. Moros et al. 05 (“ Climatic warming:a trigger for glacial iceberg surges (‘Heinrich events’) in the North Atlantic?” by Antoon Kuijpers, Hartmut Heinrich and Matthias Moros. Nr. 7, Review of Survey activities 2004, pp. 53-56 Geological Survey of Denmark and Greenland Bulletin updated July 25 2005. PDF accessed June 29, 2008) The drastic lowering of about 5°C of surface water temperature as well as the decrease of surface water salinity were thought to result from the melting of icebergs originating mainly from massive calving of the North American (Laurentide) ice sheet around Hudson Strait. For- mation and south-eastward expansion of a cold meltwater lid may have led to the weakening or cessation of the North Atlantic thermohaline circulation system. Thus, transport of warm (saline) surface water via the North Atlantic Current (NAC) to northern high latitudes decreased, resulting in a dramatic cooling in Europe. A detailed chronology established for these recurrent IRD events shows a spacing of about 11 000 years during the early glacial and about 7000 years during full glacial conditions. The significance of these massive iceberg discharge events for the understanding of the global climate evolution of the last glacial era led to the introduction of the term `Heinrich events' (H-events) for these extreme glacial iceberg episodes in the North Atlantic (Broecker et al . 1992). In addition, pos- sible links between Hevents in the North Atlantic and the so-called Dansgaard-Oeschger (D-O) cycles recorded in the Greenland ice cores were investigated by Bond et al . (1993). The glacial Greenland ice core record (Dansgaard et al . 1993) shows marked millennial scale (1500 years) climatic cycles, revealing abrupt warming (510°C) within a few decades, subsequently followed by slow cooling and terminating in an extremely cold (stadial) period lasting tens to hundreds of years.

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Ext. Ice Melt  Ice Age Warm, fast melting ice cools surface water, spurring devastating H events Moros et al. 05 (“ Climatic warming:a trigger for glacial iceberg surges (‘Heinrich events’) in the North Atlantic?” by Antoon Kuijpers, Hartmut Heinrich and Matthias Moros. Nr. 7, Review of Survey activities 2004, pp. 53-56 Geological Survey of Denmark and Greenland Bulletin updated July 25 2005. PDF accessed June 29, 2008) For icebergs to survive over large distances, as reported by the widespread IRD layers, initial ice melting must have been fast, creating an extensive cold, low- salinity surface layer. Thus, a marked cooling of the surface water was the consequence of initial, large-scale subsurface warming and melting. At lower latitudes in the North Atlan- tic simultaneous warming has been reported by various au- thors. This could explain the sudden rise in temperature a short time after the H-events, when the iceberg supply came to an end and the low salinity lid became fully mixed with the warmer water. The same mechanism of subsurface warming as a trigger for outlet glacier melting and IRD production has recently been documented for the early Holocene retreat of Jakobshavn Isbræ (Lloyd et al . in press).

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89 Ice Age

1AR- Ext. GW fails ( ) If the NAC begins to cool the Earth, even warming cannot offset its effects; Earth would be forced to wait out the ice age. Gagosian in 8 (Robert B., President and Director of Woods Hole Oceanographic Institution, May 7, http://www.whoi.edu) It is crucial to remember two points: 1) If thermohaline circulation shuts down and induces a climate transition, severe winters in the North Atlantic region would likely persist for decades to centuries—until conditions reached another threshold at which thermohaline circulation might resume. 2) Abrupt regional cooling may occur even as the earth, on average, continues to warm. Are worrisome signals developing in the ocean? If the climate system’s Achilles’ heel is the Conveyor, the Conveyor’s Achilles’ heel is the North Atlantic. An influx of fresh water into the North Atlantic’s surface could create a lid of more buoyant fresh water, lying atop denser, saltier water. This fresh water would effectively cap and insulate the surface of the North Atlantic, curtailing the ocean’s transfer of heat to the atmosphere. An influx of fresh water would also dilute the North Atlantic’s salinity. At a critical but unknown threshold, when North Atlantic waters are no longer sufficiently salty and dense, they may stop sinking. An important force driving the Conveyor could quickly diminish, with climate impacts resulting within a decade.

( ) Even if they win that a global warming doesn’t cause an ice age, our evidence explains why it wouldn’t be able to stop one either. Lovell in 6 (Jeremy, Writer for Wild Singapore, Key Warming Ocean Current Slowing Down, www.wildsingapore.com) The Atlantic Conveyor, a life-giving ocean current that keeps northern Europe warm, is slowing down, scientists said on Wednesday. If the 30 percent slowdown seen over the past 12 years is not just a blip, temperatures in northern Europe could drop significantly, despite global warming, they added. Scientists have long forecast that the Atlantic Conveyor that carries warm surface water north and cold deep water back to the equator could break down because of global warming. According to the theory, rising air temperatures cause ice caps to melt, making the water less salty and therefore less dense so it can't sink and flow back south. The scientists on Wednesday said this was the first time that observations had put flesh on the bones of the theory. "This is the first time we have observed a change in the current on a human timescale," oceanographer Harry Bryden said, noting that it had completely shut down during the ice ages. But he said the latest figures were far from proving a trend and that constant and long-term monitoring was needed. "It is like a radiator heating the atmosphere and is too important to leave to periodic observations," Bryden told a news conference to flesh out a paper he co-authored in Nature science journal.

Gonzaga Debate Institute 2008 Scholars

90 Ice Age

1AR- Ext. Need to Stop GW ( ) Even if an ice age is approaching, their proposed solution of doing nothing will exacerbate circumstances. A proactive response is necessary regarding our current climactic disaster. Their decision risks extinction. Gagosian in 8 (Robert B., President and Director of Woods Hole Oceanographic Institution, May 7, http://www.whoi.edu) Ignoring or downplaying the probability of abrupt climate change could prove costly. Ecosystems, economies, and societies can adapt more easily to gradual, anticipated changes. Some current policies and practices may be ill-advised and may prove inadequate in a world of rapid and unforeseen climate change. The challenge to world leaders is to reduce vulnerabilities by enhancing society’s ability to monitor, plan for, and adapt to rapid change. All human endeavor hinges on the vicissitudes of climate. Thus, the potential for abrupt climate change should prompt us to re-examine possible impacts on many climate-affected sectors. They include: agriculture; water resources; energy resources; forest and timber management; fisheries; coastal land management; transportation; insurance; recreation and tourism; disaster relief; and public health (associated with climate-related, vector-borne diseases such as malaria and cholera).

( ) The negative’s mindset of doing nothing is a naive framework to evaluate climactic implications. While they view global warming and an ice age as mutually exclusive events, they in fact have a direct-causal relationship, making action imperative. Gagosian in 8 (Robert B., President and Director of Woods Hole Oceanographic Institution, May 7, http://www.whoi.edu) Most of the studies and debates on potential climate change, along with its ecological and economic impacts, have focused on the ongoing buildup of industrial greenhouse gases in the atmosphere and a gradual increase in global temperatures. This line of thinking, however, fails to consider another potentially disruptive climate scenario. It ignores recent and rapidly advancing evidence that Earth’s climate repeatedly has shifted abruptly and dramatically in the past, and is capable of doing so in the future. Fossil evidence clearly demonstrates that Earth’s climate can shift gears within a decade, establishing new and different patterns that can persist for decades to centuries. In addition, these climate shifts do not necessarily have universal, global effects. They can generate a counterintuitive scenario: Even as the earth as a whole continues to warm gradually, large regions may experience a precipitous and disruptive shift into colder climates. This new paradigm of abrupt climate change has been well established over the last decade by research of ocean, earth and atmosphere scientists at many institutions worldwide. But the concept remains little known and scarcely appreciated in the wider community of scientists, economists, policy makers, and world political and business leaders. Thus, world leaders may be planning for climate scenarios of global warming that are opposite to what might actually occur.1 It is important to clarify that we are not contemplating a situation of either abrupt cooling or global warming. Rather, abrupt regional cooling and gradual global warming can unfold simultaneously. Indeed, greenhouse warming is a destabilizing factor that makes abrupt climate change more probable. A 2002 report by the US National Academy of Sciences (NAS) said, “available evidence suggests that abrupt climate changes are not only possible but likely in the future, potentially with large impacts on ecosystems and societies.”2The timing of any abrupt regional cooling in the future also has critical policy implications. An abrupt cooling that happens within the next two decades would produce different climate effects than one that occurs after another century of continuing greenhouse warming.

Gonzaga Debate Institute 2008 Scholars

91 Ice Age

1AR- Ext. GW makes conditions worse ( ) Even if they win that GW does not halt the NAC, we’ll win that it exacerbates the issues with the ocean conveyors. This is an independent reason to take action. Gagosian in 8 (Robert B., President and Director of Woods Hole Oceanographic Institution, May 7, http://www.whoi.edu) in Nature, oceanographers monitoring and analyzing conditions in the North Atlantic concluded that the North Atlantic has been freshening dramatically—continuously for the past 40 years but especially in the past decade.4 The new data show that since the mid-1960s, the subpolar seas feeding the North Atlantic have steadily and noticeably become less salty to depths of 1,000 to 4,000 meters. This is the largest and most dramatic oceanic change ever measured in the era of modern instruments.At present the influx of fresher water has been distributed throughout the water column. But at some point, fresh water may begin to pile up at the surface of the North Atlantic. When that occurs, the Conveyor could slow down or cease operating. Signs of a possible slowdown already exist. A 2001 report in Nature indicates that the flow of cold, dense water from the Norwegian and Greenland Seas into the North Atlantic has diminished by at least 20 percent since 1950. The short answer is: We do not know. Nor have scientists determined the relative contributions of a variety of sources that may be adding fresh water to the North Atlantic. Among the suspects are melting glaciers or Arctic sea ice, or increased precipitation falling directly into the ocean or entering via the great rivers that discharge into the Arctic Ocean.6 Global warming may be an exacerbating factor. Though we have invested in, and now rely on, a global network of meteorological stations to monitor fast-changing atmospheric conditions, at present we do not have a system in place for monitoring slower-developing, but critical, ocean circulation changes. The great majority of oceanographic measurements was taken throughout the years by research ships and ships of opportunity—especially during the Cold War era for anti-submarine warfare purposes. Many were taken incidentally by Ocean Weather Stations—a network of ships stationed in the ocean after World War II, whose primary duty was to guide transoceanic airplane flights. Starting in the 1970s, satellite technology superseded these weather ships. The demise of the OWS network and the end of the Cold War have left oceanographers with access to far fewer data in recent years.

Gonzaga Debate Institute 2008 Scholars

92 Ice Age

1AR- Ext. NAC changes=man made ( ) Human-induced climate change concerning thermohaline circulation risks multiple implications. Not only would the magnitude be unprecedented but recent studies prove that there is a 70% chance of circulation shutting down within the next 200 years. Owen in 5 ( James, National Geographic News Correspondent, "Mini Ice Age" May Be Coming Soon, Sea Study Warns, November 30, lexis) Absent any climate policy, scientists have found a 70 percent chance of shutting down the thermohaline circulation in the North Atlantic Ocean over the next 200 years, with a 45 percent probability of this occurring in this century. The likelihood decreases with mitigation, but even the most rigorous immediate climate policy would still leave a 25 percent chance of a thermohaline collapse. "This is a dangerous, humaninduced climate change," said Michael Schlesinger, a professor of atmospheric sciences at the University of Illinois at Urbana-Champaign. "The shutdown of the thermohaline circulation has been characterized as a high-consequence, low-probability event. Our analysis, including the uncertainties in the problem, indicates it is a high-consequence, high-probability event."

Gonzaga Debate Institute 2008 Scholars

93 Ice Age

1AR- Ext. Credible Ev. ( ) Their ‘cyclical’ argument is theoretical. Our claims that an ice age would be humaninduced via warming are grounded in concrete observations made by note-worthy scientists. Leake in 5 (Johnathan, Science Editor for The Sunday, Britain faces big chill as ocean current slows, May 8) Scientists have detected the first signs of a slowdown in the Gulf Stream — the mighty ocean current that keeps Britain and Europe from freezing. They have found that one of the “engines” driving the Gulf Stream — the sinking of supercooled water in the Greenland Sea — has weakened to less than a quarter of its former strength. The weakening, apparently caused by global warming, could herald big changes in the current over the next few years or decades. Paradoxically, it could lead to Britain and northwestern and Europe undergoing a sharp drop in temperatures. Such a change has long been predicted by scientists but the new research is among the first to show clear experimental evidence of the phenomenon. Peter Wadhams, professor of ocean physics at Cambridge University, hitched rides under the Arctic ice cap in Royal Navy submarines and used ships to take measurements across the Greenland Sea. “Until recently we would find giant ‘chimneys’ in the sea where columns of cold, dense water were sinking from the surface to the seabed 3,000 metres below, but now they have almost disappeared,” he said. “As the water sank it was replaced by warm water flowing in from the south, which kept the circulation going. If that mechanism is slowing, it will mean less heat reaching Europe.”

Gonzaga Debate Institute 2008 Scholars

94 Ice Age

1AR- Multiple tipping points ( ) We do not have to win the NAC argument. Evidence proves that the Earth has various tipping points that are climactically induced via warming with different thresholds. Triggering any of these would bring sudden and dramatic damage to our environment. Hearld 4 (Morning Herald, Sydney (Australia), World's Achilles heels, Oct. 26, 2004, http://www.heatisonline.org) Scientists noted last week that we might have less time to combat global warming than we thought. Measurements taken in Hawaii show atmospheric carbon dioxide levels have risen sharply, and inexplicably, in the past two years. Although it is too early to confirm a definite upward trend, the results came as an unwelcome surprise. John Schellnhuber, the research director at the Tyndall Centre for Climate Change Research in Britain, played a key role in identifying the dozen systems where global warming could produce sudden and dramatic environmental damage. He calls them the "tipping points" - the Achilles heels of the planet. At a conference earlier this year, Schellnhuber and other scientists called for a concerted global effort to investigate the Earth's known tipping points and to search for new ones. Only then, he said, would we be able to identify where the consequences would be felt first. "It'll take a global effort to understand these, and we have to make sure that none are activated through human actions," he says Examples of tipping points: ozone, north Atlantic current, Tibetan Plateau, and more

Gonzaga Debate Institute 2008 Scholars

95 Ice Age

1AR- TF Defense ( ) The only time an ice age can access a quick timeframe is in a world where the cause is warming. The severe temperature extremes that are byproducts of warming can cause an abrupt cooling. Calvin 97 (William H., a theoretical neurophysiologist at the University of Washington in Seattle, The Great Climate Flip Flop, http://WilliamCalvin.com/climate) ONE of the most shocking scientific realizations of all time has slowly been dawning on us: the earth's climate does great flip-flops every few thousand years, and with breathtaking speed. We could go back to ice-age temperatures within a decade — and judging from recent discoveries, an abrupt cooling could be triggered by our current global-warming trend. Europe's climate could become more like Siberia's. Because such a cooling would occur too quickly for us to make readjustments in agricultural productivity and associated supply lines, it would be a potentially civilization-shattering affair, likely to cause a population crash far worse than those seen in the wars and plagues of history. What paleoclimate and oceanography researchers know of the mechanisms underlying such a climate "flip" suggests that global warming could start one in several different ways. For a quarter century global-warming theorists have predicted that climate creep was going to occur and that we needed to prevent greenhouse gases from warming things up, thereby raising the sea level, destroying habitats, intensifying storms, and forcing agricultural rearrangements. Now we know — and from an entirely different group of scientists exploring separate lines of reasoning and data — that the most catastrophic result of global warming could be an abrupt cooling. We are in a warm period now. Scientists have known for some time that the previous warm period started 130,000 years ago and ended, 117,000 years ago, with the return of cold temperatures that led to an ice age. But the ice ages aren't what they used to be. They were formerly thought to be very gradual, with both air temperature and ice sheets changing in a slow, 100,000-year cycle tied to changes in the earth's orbit around the sun. But our current warm-up, which started about 15,000 years ago, began abruptly, with the temperature rising sharply while most of the ice was still present. We now know that there's nothing 'glacially slow' about temperature change: superimposed on the gradual, long-term cycle have been dozens of abrupt warmings and coolings that lasted only centuries.The back and forth of the ice itself started 2.5 million years ago, which is also when the ape-sized hominid brain began to develop into a fully human one, four times as large and reorganized for language, music, and chains of inference. Ours is now a brain able to anticipate outcomes well enough to practice ethical behavior, able to head off disasters in the making by extrapolating trends. Our civilizations began to emerge immediately after the great continental ice sheets melted about 10,000 years ago. Civilizations accumulate knowledge, so we now know a lot about what has been going on, what has made us what we are. We puzzle over oddities, such as the climate of Europe.

Gonzaga Debate Institute 2008 Scholars

96 Ice Age

1AR- Milankovitch is wrong ( ) Isotope analysis of a calcite cein prove that ice ages cannot be reconciled with planetary cyclicity. This devils hole theory disproves the obsolete Milankovitch theory. Pitman 6 (Sean, M.D., Loma Linda University School of Medicine, Milankovitch Cycles, http://www.detectingdesign.com/milankovitch.html) For many years, Milankovitch Theory (MT) was very popular and generally still is within the mainstream scientific community. However, fairly recently, several fundamental challenges to the validity of MT have arisen. Perhaps one of the first significant problems was noted by Wallace Broecker in his short paper published in a 1992 issue of Nature. Broecker wrote: "One of the fundamental tenets of palaeoclimate modeling, the Milankovitch theory, is called into doubt by isotope analysis of a calcite vein, just reported in Science by Winograd and colleagues. The theory, which is backed up by a compelling bank of evidence, suggests that the ice ages determined, with unprecedented accuracy, in the new record cannot be reconciled with the planetary cyclicity. . . Winograd and colleagues' evidence also turns on oxygen isotope data, this time from vein calcite coating the hanging wall of an extensional fault at Devils Hole, an aquifer in southern Nevada. In 1988, the authors published a date, 145,000 years, based on 234U-230Th dating for the end of the penultimate ice age (Termination II), marked by an increase in the 18O to 16O ratio, a change taken to mirror an increase in local precipitation. Although the date was only 17,000 year earlier than the previously accepted date of 128,000 years, if correct, this change is enough to bring Milankovitch mechanism into serious doubt. . . I remain confused. The geochemist in me says that Devils Hole chronology is the best we have. And the palaeoclimatologist in me says that correlation between accepted marine chronology and Milankovitch cycles is just too convincing to be put aside. . . One side will have to give, and maybe - just to be safe - climate modellers should start preparing themselves for a world without Milankovitch." 1

( ) Various modern findings conflict with the Milankovitch theory. This attests to the fact that the theory is outdated and inapplicable to our modern scientific concerns. Pitman 6 (Sean, M.D., Loma Linda University School of Medicine, Milankovitch Cycles, http://www.detectingdesign.com/milankovitch.html) "Empirical data reveal considerable inconsistencies of the Milankovitch theory. The main of them are the following: The climatic cyclicity for the Brunhes chronology is primarily governed by a 100 ka periodicity, attributed to eccentricity variations, whose immediate impact is disregarded in the Milankovitch theory. According to empirical data, glacial events fall on eccentricity minima, whereas under the Milankovitch theory these are mainly coupled to eccentricity maxima. [known as the causation problem] About one million years ago, the dominant climatic periodicity switched from 41 ka to 100 ka, which is at odds with the Milankovitch theory, because the variation periods of orbital elements suffered no significant changes at that time. It seems logical, that a theory, which contradicts to empirical data, is wrong. Consequently, the Milankovitch theory should be rejected, as was done with regard to it 50 years ago, as well as with regard to Croll's theory about 100 years ago."4

Gonzaga Debate Institute 2008 Scholars

97 Ice Age

TS: Milankovitch ( ) Milankovitch is wrong, it’s scientifically proven. The only thing that stops the debunking of his theory is scientist consensus – so many others have based work off of his. This new study disproves past consensus. Pitman 6 (Sean, M.D., Loma Linda University School of Medicine, Milankovitch Cycles, http://www.detectingdesign.com/milankovitch.html) "We have been studying the cycles of the ice ages using data collected from sea-floor cores, Greenland ice, and other terrestrial sources. We have published a careful spectral analysis that shows that the "standard" Milankovitch theory for the glacial cycles is wrong, and we have proposed an alternative explanation: that the cycles are driven by extraterrestrial accretion."5 In short, because of the many problems with MT, especially the causality problem where the ice and deep see core data say the Earth should be warm when MT says it should be cold, and visa versa, Muller believes that MT is simply wrong and should be replaced by another theory. He has even come up with a ready theory to explain away at least one of the major problems with MT - extraterrestrial accretion. Muller basically believes that as the Earth travels around the Sun it does not always stay in the same plane. Like a slightly wobbly record on a record player, the Earth will sometimes be above the plane and sometimes below the plane. This happens to occur in a cyclic pattern of about 100,000 years. Muller believes that as the Earth moves out of plane, it picks up more cosmic dust than usual, which affects the weather of the Earth in 100,000 year cycles. "So far, Muller and MacDonald have been unable to get their full paper, detailing their work, published, despite their considerable credentials. It's been rejected by Science. It's been rejected by Nature three times - the third time as recently as June - though the editors did request, and published, a shorter version summarizing their findings last November. Why? Muller pulls open a long file drawer, crammed with papers. 'Here it is. Essentially everything that's been published for the last twenty years assumes the Milankovitch model. I think it's very hard for people in this field, and all the referees to whom our paper has been submitted are working in this field, to accept our paper. They'd have to say that most of their own work for the past twenty years is fundamentally flawed.'" 6 Isn't that interesting? Milankovitch theory is so engrained in the scientific community that even an otherwise well-respected mainstream scientists seems to be having trouble getting anything significant published that fundamentally challenges Milankovitch.

Gonzaga Debate Institute 2008 Scholars

98 Ice Age

1AR- Emilani is wrong ( ) Emilani’s defense of Mil is based on fabricated evidence. Our evidence cites the specific problems and scientific details that make Mil’s theory wrong. Pitman 6 (Sean, M.D., Loma Linda University School of Medicine, Milankovitch Cycles, http://www.detectingdesign.com/milankovitch.html) We were puzzled by the table in the Scientific Correspondence by Emiliani. He rejects the conventionally used terminations (glacial-interglacial transitions) as time markers and focuses on bathythermals (the coldest portions of glacial cycles), which he deems to be sharper and therefore more precise time markers. He claims that bathythermals in the Devils Hole delta 18O chronology occur at times when the orbital parameters of obliquity and eccentricity are both "low", as determined from Berger's figures, thereby supporting Milankovitch mechanism. Unfortunately, Emiliani does not specifically define what he means by the critical terms "low" or "when they approach coincidence", but we assume he takes "low" to mean the times when both obliquity [41ka period] and eccentricity [100ka period] were at a minimum, or obliquity was at a minimum and eccentricity was less than at least the long-term (0-600,000-year) average value. We show in the figure the seven astronomical "low" events that Emiliani gives in the third column in his table, as well as the seven (but not identical) events that satisfy the specific definition of astronomical low conditions using data in reference 4. We were puzzled as to why Emiliani omitted the two-well defined "low" events at 395,000 and 517,000 years and note that they do not correspond to bathythermals in either the Devils Hole or the marine delta 18O chronologies. Indeed, the 395,000-year "low" event occurs during a peak interglacial time. We also note that Emiliani's designation of a "low" event at 555,000 and 150,000 years does not fit the earlier stated definitions. Also shown in the figure are the eight major delta 18O minima, denoting times of full glacial climate, found in the Devils Hole chronology, and the subset of six events that Emiliani gives in the second column in his table. He did not mention the two Devils Hole isotope minima at 223,000 and 173,000 years, which do not correspond to any astronomical "low" event. In comparing the astronomical "low" events predicted by the specific definition with the minimal isotope events found in the Devils Hole chronology, one sees that although there are four 'matches', there are six 'nonmatches', twice when a bathythermal would be predicted but did not happen, and four times when one did occur but not during an astronomical "low" event. Thus the astronomical conditions that Emiliani specifies is neither sufficient nor necessary for the occurrence of bathythermals." 3 So, it seems that Emiliani manipulated the data quite extensively in order to make it fit in with MT. Though this was most certainly done subconsciously, it highlights the pitfalls of bias - of having a strong belief that a particular view or theory is almost certainly "true". This does not mean that such a belief isn't good to have in many cases. It is just that one should be aware of one's own inescapable biases when approaching and interpreting new or even old data.

Gonzaga Debate Institute 2008 Scholars

99 Ice Age

1AR- Ext. Warming caused past IA ( ) Their solar cycle arguments ignore the fact that warming played a factor in past ice ages. Modern scientific evidence proves. Presse 5 (Agence France-Presse, Writer for The Heat is Online; Global Warming: Shutdown Of Atlantic Current Would Ravage Food Stocks, March 31www.heatisonline.org) Temporary slowdowns in the Atlantic's circulation system have occurred in the past, most notably after the end of the last Ice Age, about 10,000 years ago, said Schmittner. Isotope traces from Greenland icecores suggest there were bursts of rapid warmings of 10 C (18 F), which melted huge amounts of Arctic ice. This influx, because it comprised cold freshwater, sank to the bottom of the ocean floor, essentially acting like a giant sandbag thrown on the conveyor belt, braking its movement. Today, Earth is considered to be in an "interglacial" period - a balmy period between ice ages. But scientists say there is a possibility of another big temperature rise induced by man-made global warming, caused by the spewing of fossil-fuel greenhouse gases into the atmosphere. One scenario, considered outlandish only a few years ago but now increasingly taken seriously, is that a fast melt of part of the Greenland icesheet could slow or stop the warm-water circulation in the North Atlantic, with catastrophic, long-term results.

Gonzaga Debate Institute 2008 Scholars

100 Ice Age

1AR- Ext: High Risk of NAC failure ( ) Your journal reviews don’t matter. Science shows that the enormous influx of freshwater caused by glacier melting severely affects the NAC. This makes global warming one of the largest factors of the ocean conveyor belt with a 70% probability of shutting down the NAC. Owen in 5 ( James, National Geographic News Correspondent, "Mini Ice Age" May Be Coming Soon, Sea Study Warns, November 30, lexis) "This movement carries a tremendous amount of heat northward, and plays a vital role in maintaining the current climate," Schlesinger said. "If the thermohaline circulation shut down, the southern hemisphere would become warmer and the northern hemisphere would become colder. The heavily populated regions of eastern North America and western Europe would experience a significant shift in climate." Higher temperatures caused by global warming could add fresh water to the northern North Atlantic by increasing the precipitation and by melting nearby sea ice, mountain glaciers and the Greenland ice sheet. This influx of fresh water could reduce the surface salinity and density, leading to a shutdown of the thermohaline circulation. "We already have evidence dating back to 1965 that shows a drop in salinity around the North Atlantic," Schlesinger said. "The change is small, compared to what our model needs to shut down the thermohaline, but we could be standing at the brink of an abrupt and irreversible climate change." To analyze the problem, Schlesinger and his colleagues first used an uncoupled ocean general circulation model and a coupled atmosphere-ocean general circulation model to simulate the present-day thermohaline circulation and explore how it would behave in response to the addition of fresh water. They then used an extended, but simplified, model to represent the wide range of behavior of the thermohaline circulation. By combining the simple model with an economic model, they could estimate the likelihood of a shutdown between now and 2205, both with and without the policy intervention of a carbon tax on fossil fuels. The carbon tax started out at $10 per ton of carbon (about five cents per gallon of gasoline) and gradually increased. "We found that there is a 70 percent likelihood of a thermohaline collapse, absent any climate policy," Schlesinger said. "Although this likelihood can be reduced by the policy intervention, it still exceeds 25 percent even with maximal policy intervention." Because the risk of a thermohaline collapse is unacceptably large, Schlesinger said, "measures over and above the policy intervention of a carbon tax -- such as carbon capture and sequestration -- should be given serious consideration."