How many pounds of carbon dioxide
are added to the atmosphere
by burning one gallon of gas?
A gallon of gasoline weighs 6.2 pounds, consisting mostly of carbon, plus a small amount of hydrogen and a few impurities. Through combustion each carbon atom combines with two atoms of heavier oxygen atoms, resulting in 19.8 pounds of carbon dioxide in the atmosphere.
How much prehistoric plant matter did it take to make that gallon of gas? About 196,000 pounds, or as much as is found in one-acre of wheat. Americans burn up about 131 billion gallons of gas every year, or the equivalent of 25 quadrillion pounds of prehistoric biomass. Since 1751, our species has used the equivalent from all types of fossil fuels of about 13,300 years of biomass production by all plants on earth.
The stability of the climate is threatened by greenhouse gas emissions, especially carbon dioxide released from fossil fuels and deforestation. The ecosystem naturally recycles an estimated 225 billion tons of carbon dioxide each year from processes like respiration, decay, and fires. Most of the carbon is removed from the atmosphere by forests and by microorganisms in the oceans. Human activity has tipped the balance by adding 5.5 billion tons of carbon dioxide to the air each year from fossil fuel use. Deforestation contributes another 2.2 billion tons of carbon a year to the atmosphere while simultaneously reducing the total amount of forests available to remove carbon. Although the amount of carbon dioxide we add to the atmosphere seems small by comparison to the amount recycled by nature every year, we are nevertheless greatly increasing the proportion of carbon dioxide in the atmosphere.
Excluding water vapor, the atmosphere consists of 78% nitrogen, 21% oxygen and 0.9% argon. Other traces gasses, mostly carbon dioxide, make up an additional .039% of the atmosphere, up from 0.028% prior to industrialization.
Two-atom molecules like nitrogen and oxygen vibrate at high frequencies, so they do not absorb much of the heat that normally reflects of the earth and bounces back into space. But 3-atom molecules like carbon dioxide, water vapor, nitrous oxide and sulfur dioxide all absorb heat and reflect it back down on the earth, trapping heat in like a window, hence the term "greenhouse effect". Carbon dioxide and other trace gasses may be a very small part of the atmosphere, but they keep the earth's surface about 59 degrees warmer than it would be without these gasses, so even a small increase in the amount of greenhouse gasses can have a big effect on the climate.
While it is virtually certain that altering the atmosphere will alter the earth's climate and weather patterns, it is difficult to predict how it will change. Global warming is the most likely scenario, and already we have melted about 40% of the arctic ice cap in less than 30 years. Global warming could flood coastal cities, increase the frequency of hurricanes and other weather-related disasters and transform crucial croplands into deserts. Paradoxically, global warming also increases atmospheric humidity, which can increase precipitation and potentially trigger an ice age. Rather than wait to find out what happens, we would likely be wise to alter human behaviors to stop the buildup of greenhouse gasses.
Sea levels rose by about five inches during the last century, but this may have been the result of an ongoing warming trend since the end of the last ice age. The ocean absorbs additional heat each year, causing the water to expand and sea levels to rise. Actual sea level measurements can be misleading, since land masses like Scandinavia, northern Canada and Greenland that were once compressed under the weight of glacial ice are actually rising, making it appear that sea levels are dropping. On the other hand, the Nile Delta, eastern China, Bangladesh, and the eastern seaboard of the U.S. are all subsiding-that is sinking- due to ground water removal and other factors. In these places the sea level appears to have risen more than five inches. Measurements taken with the aid of satellites have helped to more accurately determine worldwide sea levels.
Half of the world's population lives in coastal areas. In the Netherlands where much of the country is already below sea level, it will cost an estimated $10 billion dollars to raise the dikes high enough to keep out the rising sea. In the U.S., Massachusetts alone is expected to lose 250 square miles of land during this century. In impoverished countries like Bangladesh were 120 million people live in delta regions, rising sea levels will wipe out their fertile lands or contaminate the aquifers with salt water, causing a mass exodus from the land, but with no place to go. Some low-lying islands in the Pacific have already disappeared to rising sea levels. The island nation of Tuvalu, with a population of 10,000 people, is also expected to disappear in the coming decades. A similar fate awaits a chain of islands called the Maldives in the Indian Ocean where the highest point is 8 feet above sea level. The approximately 250,000 people there are very aware of the problem of global warming, but powerless to do anything about it.
_____. "Burning A Gallon Of Gas Is Like Tossing a 5-Pound Bag Of Charcoal Up In The Air." The Mercury's Rising. Catlett, VA. February 2000. Page 4.
_____. "Island Nation Struggles To Keep Its Head Above Water." The Mercury's Rising. Catlett, VA. February 2000. Page 8.
_____. "Trouble in Paradise - The Maldives." The Mercury's Rising. Catlett, VA. May 2000. Pages 6-7.
_____. "Who Can Hold Back The Sea?" The Mercury's Rising. Catlett, VA. February 2000. Page 7.
_____. "Will the Arctic Ocean Lose All Its Ice?" The Mercury's Rising. Catlett, VA. May 2000. Page 8.
DiChristina, Mariette. "Reversing the Greenhouse." Popular Science. August 1991. Pgs. 78-80.
Easterbrook, Gregg. "Return of the Glaciers." Newsweek. November 23, 1992. Pg. 62-63.
Hawken, Paul with Amory & Hunter Lovins. Natural Capitalism: Creating the Next Industrial Revolution. Little, Brown & Co.: Boston, New York. 1999.
Kruglinski, Susan. "What's in a Gallon of Gas?" Discover. April 2004. Page 11.