Ransomstephens 10thgradeglobalwarming

10th Grade-level Prerequisite for the Global Warming Debate By Ransom W. Stephens, Ph.D. Copyright 2009 When scientific questions are elevated to public significance they are debated in an utterly nonscientific way – eloquence, prejudice, even ridicule sway public opinion when facts are perceived as too arcane for the populace to understand. So today, I invite you to use science that you learned in high school to address a fundamental point in the global warming debate. Is it reasonable to expect the general populace to be scientifically literate? We expect citizens to be able to read, why not expect them to remember a little high school science? Or is the problem that scientists so rarely invite the populace to the argument that it is unreasonable to expect them to know the language? Here’s your invitation: Calculate the percentage increase in the carbon dioxide content of the atmosphere due to the oil that people burned last year. First, we’ll figure out how many carbon dioxide (CO2) molecules are released in the process of burning oil. Then we’ll calculate the volume of that CO2 and compare it to the total volume of CO2 that was in the air to begin with. Since we’re not experts, we’ll have to make a few approximations and assumptions that will pull us 20-30% from the actual value. Keep in mind that, by dotting every “t” and crossing every “i”, the experts can make the calculation with an uncertainty of less than 1%. In the process you’ll remember things from high school and will have to do some arithmetic, but no more than it takes to prepare your taxes (sorry to bring that up). Hopefully you’ll discover that you’re capable of addressing the global warming debate in a scientific way, just like you’re capable of addressing health care, social security, or the Iraq war in a political way.

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Here we go: Gasoline is made up of hydrocarbons, a mix of long chains that are described by CnH2n+2. The “C” represents a carbon atom, and the “H” a hydrogen atom. The carbons are connected in a chain that is n carbons long. Each carbon has two hydrogens attached, except at each end of the chain where they have three. The length of the chain, n, is almost always a number between 5 and 12 – let’s pick n = 8 and use C8H18 – this is our first assumption. Now you need to find some of the brain cells that you filled in high school to recall an 18th century Italian lawyer named Avogadro who was interested in chemistry. He figured out that the atomic mass of an element in grams contains 6×1023 atoms – a ridiculously large number called a “mole” (this should dredge up some bad puns from 9th grade). Since the atomic mass of carbon is about 12 grams, and that of hydrogen is about 1 gm, the atomic or, more properly, the molecular mass of C8H18 is about 8×12 + 18 = 114 gm. When gas is burned, almost every carbon atom ends up in a carbon dioxide molecule, CO2, so when 114 gm of gas are burned about 8×6×1023 = 48×1023 CO2 molecules are released into the air. Oil is counted by the barrel, and a barrel holds 159 liters which is about 159,000 gm (350 pounds or so). Dividing that by the molecular mass of C8H18, 114 gm, and we get 159,000/114 = 1400 moles of C8H18 in each barrel which, when burned, results in 1400×48×1023 = 6.7×1027 CO2 molecules per barrel of gas. At the Department of Energy’s estimate of 80 million barrels each day, that’s 80,000,000×6.7×1027 = 5.4×1035 CO2 molecules per day, or 365×5.4×1035 = 2×1038 CO2 molecules per year. To estimate how much CO2 was in the atmosphere to begin with, start by calculating the volume of the whole atmosphere. Since we’re not experts, we can be lazy about our facts. The air is pretty thin at the top of Mount Everest, which is 8800 meters high (about 5.5 miles) so let’s set the height at 9000 m. To counter that underestimate, we’ll assume that the atmosphere is a Copyright 2009 Ransom Stephens

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uniform shell of air that has about the same temperature and pressure as it does on the beach in San Diego where it’s much thicker than at the top of Everest. The average radius of Earth is about 6 million meters, so the volume of the atmosphere is 4×

π×(6×106 m)2×(9,000 m) = 4×1018 cubic meters. We need a reference point. I have this old book, Physical Constants, by W.H.J. Childs published in 1934 that says the atmosphere was about 0.03% CO2.This means that we start with 0.0003×4×1018 = 1.2×1015 cubic meters of CO2 which is 1.2×1018 liters. Perhaps the coolest thing you learned in 9th or 10th (maybe 7th) grade is that, at standard temperature and pressure (beach in San Diego), one Mole (6×1023) of gas molecules occupy 22.4 liters of volume. Therefore, in 1934, the atmosphere contained a total of about 6×1023×1.2× 1018/22.4 = 3.2×1040 CO2 Molecules. At last we can compare the number of CO2 molecules produced by people burning oil each year (1.8×1038) with the number that were present in the atmosphere in 1934 (3.2×1040). which means that people burn enough gas to increase the atmospheric concentration of CO2 by 100×2× 1038/3.2×1040 = 0.6% each year. In a decade we increase the CO2 content by about 6% - just by burning gas. If we include coal (about 22 million kg burned each day), natural gas, cigarettes, incense, ethanol, vegetable oil, wood, or almost anything else that burns, the result is about twice what we got from oil alone. Our 10th grade-level calculation shows that the 35% increase in CO2 over the last 100 years reported by the experts can easily be accounted for by human activity.

Copyright 2009 Ransom Stephens

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The next question in the debate: “Does CO2 hold more heat than the other constituents of air?” requires an experiment. If we blow up two balloons, one with air and one with CO2 and shine a lamp on them we’ll see that CO2 heats up about 15% faster than air. This is the reason that CO2 is a “greenhouse gas,” a given amount of heat increases the temperature of CO2 more than that same amount of heat increases the temperature of air. Our results support the hypothesis that human activity, in particular, burning stuff, has caused the atmosphere to heat up more than it otherwise would – global warming. Since our result begins and ends with science at its most simple, any argument to the contrary disputes common sense. That’s okay, though, common sense doesn’t win every argument in science; it’s just a starting point. There are many other questions to ask: could our 0.6% increase per year in CO2 be absorbed by the ocean without affecting the atmosphere? Could an increase in CO2 be compensated by an increase in plant growth? Could we please not do arithmetic on Sunday morning? and so on. By now, I hope you’ll agree that these questions can be addressed without aspiring to eloquence or resorting to ridicule. The debate can continue scientifically and, with the level of scientific literacy achieved in high school, we can all participate.

About the author: After teaching relativistic quantum field theory to 8th graders, Ransom Stephens came to believe that Americans are more scientifically literate than they realize. Contact Ransom at www.ransomsnotes.com and read his book www.TheGodPatent.com.

Copyright 2009 Ransom Stephens