Lecture(human Impact Environment)

Human Impact on the Biosphere

Human Impacts  Humans are using energy and altering 

the environment at astonishing rates  We are altering natural processes before 

we even understand them

Developing vs. Developed  In

developing countries, per capita

resource use is high but growing, as is population size  In

developed countries, population

growth has slowed but per capita resource use is already high

Pollutants  Substances with which an ecosystem 

has had no prior evolutionary experience  No adaptive mechanisms are in place to 

deal with them

Air Pollutants  Carbon  Sulfur

oxides

oxides

 Nitrogen

oxides

 Volatile

organic compounds

 Photochemical  Suspended

oxidants

particles

Chemistry 101  Acid

anhydrides: oxides of nonmetals  CO , NO and SO 2 2 3  These

react with water to form oxyacids.  CO 2 + H2O ---> H2CO3 (carbonic acid)  HNO and H SO are also formed in 3 2 4 the atmosphere

Acid Rain and Architecture  On

campus we have some architectural damage attributable to acid rain.  The limestone lentils and pillars on the older building are dissolving away! H

SO4(aq) + CaCO3(s)  H2O(l) + CO2(g) +CaSO4(aq) 2

Industrial Smog  Gray-air  Forms

smog

over cities that burn large

amounts of coal and heavy fuel oils; mainly in developing countries  Main

components are sulfur oxides

and suspended particles

Photochemical smog  Brown-air  Forms

smog

when sunlight interacts with

components from automobile exhaust  Nitrogen  Hot

oxides are the main culprits

days contribute to formation

Thermal Inversion  Weather

pattern in which a layer of cool, dense air is trapped beneath a layer of warm air cool air warm inversion air cool air

Cities Are Often Plagued with Thermal Inversions

Acid Deposition (Stopped)  Caused

by the

release of sulfur and nitrogen oxides  Coal-burning

power

plants and motor vehicles are major sources

Effect of Ozone Thinning  Increased

amount of UV radiation reaches Earth’s surface

 UV

damages DNA and negatively affects human health

 UV

also affects plants, lowers primary productivity

Ozone Thinning 

In early spring and  summer ozone layer  over Antarctica thins



Seasonal loss of  ozone is at highest  level ever recorded

South America

Antarctica

Ozone in Earth’s Atmosphere

Ozone Concentration from 1962 to 1996

http://www.igf.edu.pl/igf/atmosphere.htm

Recipe for Ozone Loss 

“The polar winter leads to the formation of the polar

vortex which isolates the air within it. 





Cold temperatures form inside the vortex; cold enough for the formation of Polar Stratospheric Clouds (PSCs). As the vortex air is isolated, the cold temperatures and the PSCs persist. Once the PSCs form, heterogeneous reactions take place and convert the inactive chlorine and bromine reservoirs to more active forms of chlorine and bromine. No ozone loss occurs until sunlight returns to the air inside the polar vortex and allows the production of active chlorine and initiates the catalytic ozone destruction cycles. Ozone loss is rapid. The ozone hole currently covers a geographic region a little bigger than Antarctica and extends nearly 10km in altitude in the lower stratosphere”

http://www.atm.ch.cam.ac.uk/tour/part3.html

Protecting the Ozone Layer  CFC

production has been halted in

developed countries, will be phased out in developing countries  Methyl  Even

bromide will be phased out

with bans it will take more than

50 years for ozone levels to recover

Generating Garbage  Developed countries generate huge 

amounts of waste  Paper products account for half the total 

volume  Recycling can reduce pollutants, save 

energy, ease pressure on landfills

Garbage Barge Solution

Landfills

Land Use  Almost

21 percent of Earth’s land is used for agriculture or grazing

 About

half the Earth’s land is unsuitable for such uses

 Remainder

could be used, but at a high ecological cost

Green Revolutions  Improvements  Introduction

in crop production

of mechanized

agriculture and practices requires inputs of pesticides, fertilizer, fossil fuel  Improving

genetic character of crop

plants can also improve yields

Data From the UN

INDIA REACHING 1 BILLION ON AUGUST 15: NO CELEBRATION PLANNED Lester R. Brown and Brian Halweil

 Falling

water tables are now also threatening India's food production.  The International Water Management Institute (IWMI) estimates that withdrawals of underground water are double the rate of aquifer recharge.  As a result, water tables are falling almost everywhere. http://www.worldwatch.org/node/1656

Aquifer Depletion

http://www.uwgb.edu/dutchs/EarthSC202Notes/Grndh2o.htm

Deforestation  Removal of all trees from large tracts of 

land  38 million acres logged each year  Wood is used for fuel, lumber  Land is cleared for grazing or crops

Clear Cutting of Forests

Effects of Deforestation  Increased

leaching and soil

erosion  Increased

flooding and sedimentation of downstream rivers

 Regional  Possible

precipitation declines amplification of the

Regions of Deforestation  Rates

of forest loss are greatest in

Brazil, Indonesia, Mexico, and Columbia  Highly

mechanized logging is

proceeding in temperate forests of the United States and Canada

“A heavy duty tree chopper for cutting down trees in a logging operation.”

Rainforests

Forests Burning

Reversing Deforestation  Coalition

of groups dedicated to

saving Brazil’s remaining forests  Smokeless

wood stoves have saved

firewood in India  Kenyan

of trees

women have planted millions

NAIROBI (AFP) Feb 23, 2005 NAIROBI (AFP) Feb 23, 2005 “Kenyan Nobel peace laureate Wangari Maathai on Wednesday urged developing nations to help fight global warming and support the Kyoto Protocol on climate change by joining her tree-planting campaign.”

Destroying Biodiversity  Tropical rainforests have the greatest 

variety of insects, most bird species  Some tropical forest species may prove 

valuable to humans  Our primate ancestors evolved in forests 

like the ones we are destroying 

Primates Many primate species are threaten or endangered.

Desertification  Conversion of large tracts of grassland to 

desertlike conditions   Conversions of cropland that result in 

more than 10 percent decline in  productivity

Global Desertification Vulnerability

The Dust Bowl  Occurred

in the 1930s in the Great

Plains  Overgrazing

and prolonged drought left the ground bare

 1934

winds produced dust storms that stripped about 9 million acres of topsoil

Caption: "Dust Over Texas." Huge boiling masses of dust that blocked out the sun were common sights in Texas during the Dust Bowl years. In: "To Hold This Soil", Russell Lord, 1938. Miscellaneous Publication No. 321, U.S. Department of Agriculture.

Human Tragedy

Ongoing Desertification  Sahel

region of Africa is undergoing

rapid desertification  Causes

are overgrazing,

overfarming, and prolonged drought  One

solution may be to substitute

native herbivores for imported cattle

Linear dunes of the Sahara Desert encroach on Nouakchott, the capital of Mauritania. The dunes border a mosque at left (photograph by Georg Gerster).

Water Use and Scarcity  Most of Earth’s water is too salty for 

human consumption  Desalinization is expensive and 

requires large energy inputs  Irrigation

of crops is the main

use of freshwater

Mean Annual Precipitation

Water Distribution

Negative Effects of Irrigation  Salinization,

mineral buildup in

soil  Elevation

of the water table

and waterlogging  Depletion

of aquifers

Salinization, mineral buildup in soil

http://waterquality.montana.edu/docs/methane/irrigation_suitability.shtm

Groundwater  Aquifers

- Porous layers of sand, gravel, or rock lying below the water table. – Artesian - Pressurized aquifer intersects the surface. (Water flows without pumping)

 Recharge

Zone - Area where water infiltrates into an aquifer. – Recharge rate is often very slow.  Presently,

groundwater is being removed faster than it can be replenished in many areas.

Depleting Groundwater  Groundwater

is the source of nearly 40% of fresh water in the US. – On a local level, withdrawing water faster than it can be replenished leads to a cone of depression in the water table,  On

a broader scale, heavy pumping can deplete an aquifer. – Ogallala Aquifer  Mining non-renewable resource.

Depleting Groundwater

Ogallala Aquifer  Extends

from southern South Dakota

to central Texas  Major

source of water for drinking

and irrigation  Overdrafts

have depleted half the

water from this nonrenewable source

Ogallala Aquifer  “The

Ogallala Aquifer within the boundaries of the North Plains Groundwater Conservation District is declining at an average of 1.74 feet per year (1,082,631 acre ft).”  The aquifer is cut off from  natural recharge sources. http://www.npwd.org/Ogallala.htm

Aquifer Problems

Sink Holes and Karst Topography

CaCO3 + H2SO4  CaSO4 + H2O +CO2 http://www.soils.umn.edu/academics/classes/soil2125/doc/1-snkle.htm

Water Pollutants  Sewage  Animal

wastes  Fertilizers  Pesticides  Industrial chemicals  Radioactive material  Excess heat (thermal pollution)

Groundwater Pollution

Wastewater Treatment  Primary

treatment

– Use of screens and settling tanks – Addition of chlorine to kill pathogens  Secondary

treatment

– Microbes break down organic matter  Tertiary

treatment removes additional toxic substances; rarely used

Sewage Treatment  More

than 500 pathogenic bacteria, viruses, and parasites can travel from human or animal excrement through water.  Natural Processes – In many areas, outdoor urination and defecation is the norm.  When

population densities are low, natural processes can quickly eliminate waste.

Municipal Sewage Treatment  Primary

Treatment - Physical separation of large solids from the waste stream.  Secondary Treatment - Biological degradation of dissolved organic compounds. – Effluent from primary treatment transferred into trickling bed, or aeration tank  Effluent

from secondary treatment is usually disinfected (chlorinated) before release into nearby waterway.

Municipal Sewage Treatment  Tertiary

Treatment - Removal of plant nutrients (nitrates and phosphates) from secondary effluent. – Chemicals, or natural wetlands.

 In

many US cities, sanitary sewers are connected to storm sewers. – Heavy storms can overload the system, causing by-pass dumping of raw sewage and toxic runoff directly into watercourses.

Municipal Sewage Treatment

CSO Tunnels and Treatment Facilities (Atlanta, GA 2005) 

“The tunnel is part of a storage and treatment system that involves capturing and storing combined sewer overflows. The overflows are stored in a large underground tunnel in bedrock similar to the rock that comprises Stone Mountain. When a storm is over, the captured CSO volume is conveyed to a separate treatment system for removal of pollutants and reduction of harmful bacteria with sodium hypochlorite disinfection followed by dechlorination with sodium bisulfite before discharge to receiving waters. The City is building two facilities, the West Area CSO storage

Milestone Completion Date for West Tunnel October 2007

These will collect storm water for treatment.

http://www.cleanwateratlanta.org/CSOTunnels/

Oxygen-Demanding Wastes  Water

with an oxygen content > 6 ppm will support desirable aquatic life. – Water with < 2 ppm oxygen will support mainly detritivores and decomposers.

 Oxygen

is added to water by diffusion from wind and waves, and by photosynthesis from green plants, algae, and cyanobacteria. – Oxygen is removed from water by

Oxygen-Demanding Wastes  Biochemical

Oxygen Demand Amount of dissolved oxygen consumed by aquatic microorganisms. – Dissolved Oxygen Content - Measure of dissolved oxygen in the water.

 Effects

of oxygen-demanding wastes on rivers depend on volume, flow, and temperature of river water. – Oxygen Sag - Oxygen levels decline downstream from a pollution source as decomposers metabolize waste

Oxygen Sag

Water Wars?  Per

capita amount of freshwater

available is decreasing  International

conflicts over water

use and quality have already occurred  Building

dams or dumping

pollutants effect countries downstream

Weiss Lake Organization Declares War!

“Weiss Lake Improvement Association is the environmental and ecological watchdog for Weiss Lake and against ‘Metro Atlanta’ from taking our WATER.” (Coosa River Drainage)

Energy Use (Stopped here.  9/11/08)  Only 10 percent of energy used in 

developed countries is from  renewable sources  Less developed countries rely more 

heavily on renewable sources  (primary biomass)

Fossil Fuels  Coal,

oil, natural gas

 Main

energy source of

developed countries  Burning

of fossil fuels

contributes to global warming

http://faculty.virginia.edu/setear/courses/globwarm/images.htm

Oil  Reserves  Many

are declining

reserves are in ecologically

fragile wilderness areas  Environmental

costs of extracting

and transporting reserves from such areas are high

Total Energy Consumption

Domestic Product

Oil and Gas Injection Wells 

Typically, when oil and gas are extracted, large amounts of salt water (brine) are also brought to the surface. This salt water can be very damaging if it is discharged into surface water.

Coal  Extensive  Mining

reserves exist

is very destructive

 Burning

coal releases sulfur

dioxides that cause acid deposition

Coal Strip Mining

EPA targets utilities’ mercury pollution  “Coal-burning

power plants in the United States now emit an estimated 48 tons a year of mercury, and the EPA rule aims to reduce that to 31.3 tons in 2010, 27.9 tons in 2015, and 24.3 tons in 2020.”

Updated: 3:03 p.m. ET March 15, 2005 (AP) http://www.msnbc.msn.com/id/6448213/did/7185001

How Mercury Gets into the Food Chain

http://www.msnbc.msn.com/id/6448213/did/7185001

EPA’s Cap and Trade Policy EPA sets yearly limits on mercury emissions Industry is assigned a quantity of tradable mercury emissions certificates These are bought and sold by power companies (bid/ask system). Some companies “over pollute” and some “under pollute” Each year the EPA reduces allowable emission quantities leading to an economic solution to pollution

Nuclear Energy  Used

extensively in some energypoor developed countries

 Little

support in the United States

 Emits

fewer air pollutants than burning coal, but creates radioactive wastes

 Potential

for meltdown

Chernobyl Accident - 1986  Core

meltdown at a nuclear power plant in the Ukraine

 31

immediate deaths, radiation sickness and death for others

 Cloud

of radiation spread by winds across Europe

 Long-term

health impacts downwind

Map of Chernobyl Region

Nuclear Power in France 

“When the Civaux nuclear power plant comes on line sometime in the next 12 months, France will have 56 working nuclear plants, generating 76% of her electricity.” (Frontline)

 Some

Alternatives……

Solar­Hydrogen Energy  Photovoltaic cells use sunlight energy 

to split water   Hydrogen gas produced in this way 

can be used as fuel or to generate  electricity  Clean, renewable technology

Fuel Cells

Farmed Hydrogen  Photobiological

Hydrogen

Production  Aquatic algae bio-engineered to produce hydrogen gas rather than sugars via photosynthesis  Place algae in a clear tube, reduce sulfur, place in sunlight, and collect the hydrogen!

Hydrogen from Algae

Chlamydomonas reinhardt

MIT Algae Photobioreactor

http://www.youtube.com/watch?v=E nOSnJJSP5c&feature=related

Shec – labs System Mirror array focuses sunlight on a hydrogen generator (850 C) Waste gases (methane, CO2, etc) are heated and converted to hydrogen gas. Hydrogen gas (plus O2) is used to power fuel cells.

www.shec-labs.com/press/images.php

Wind Energy  An

indirect use of solar energy

 Wind

farms are arrays of

turbines  Can

supplement needs of some

regions but is not dependable enough on it own

Giant wind turbines at Aapua, Sweden

http://www.xahlee.org/Whirlwheel_dir/windturbine.html

San Gorgonio Field Near Palm Springs, CA

Overview of Wind Energy in California 



“the year 2004, wind energy in California produced 4,258 million kilowatt-hours of electricity, about 1.5 percent of the state's total electricity. According to the Electric Power Research Institute, the cost of producing wind energy has decreased nearly four fold since 1980. The levelized cost of energy from wind turbines in 1993 was about 7.5 cents per kilowatt/hour. With current wind research and development efforts, the Energy Commission estimates that newer technologies can reduce the cost of wind energy to 3.5 cents per kilowatt-hour.”

http://www.energy.ca.gov/wind/overview.html

Electricity Costs (2003)

Fusion  Energy

is released when atomic nuclei fuse

 This

process produces solar energy

 Attempts

to mimic this process on Earth require use of lasers, magnetic fields

 Not

yet a commercially viable energy source

Fusion Reaction Note: Fusion tutorial available at website below.

http://hif.lbl.gov/tutorial/tutorial.html

Changes in the World of Life   Adaptations

of species have

changed the environment  Photosynthetic

organisms that

arose during the Proterozoic altered the atmosphere by adding oxygen  Change

is natural

Humans and Change Unlike previous species, human have the capacity to observe and make decisions about the changes they bring about. A couple of examples of using misplaced resources….

Gas for the Greenhouse  "By

transporting CO2 by pipeline from the Shell refineries in Pernis to the cultivators in the Westland, the emission of greenhouse gas can be greatly reduced. At the same time, the farmers can save a lot of money; there is no more need for them to produce their CO2 themselves".

http://www.radionetherlands.nl/features/science/051107rf

OCAP Waste CO2 Used in Greenhouses

6 CO2

+

6 H2O

+

sunlight 

C6H12O6

+

6O2

“Anything Into Oil” Changing World Technologies, Inc. “…Carthage, Missouri, turkey plant accumulates 1.3 million gallons a day of turkey grease, guts, fat, and feathers that is stored in lagoons and sent to waste treatment facilities” Estimated production of fuel oil, 500 barrels a day. http://www.perc.org/perc.php?id=290 “Twenty tons of slaughterhouse turkey parts, freshly dumped by a truck, await processing into oil, gas, and minerals at the thermal conversion process plant in Carthage, Missouri. When the plant reaches full capacity in the fall, it will process 10 dump trucks of leftovers, one tanker truck of blood, and one tanker truck of discarded restaurant grease every 24 hours.”