Biology 101

Global Warming

Global Warming is thought to be caused by the Greenhouse effect , a buildup of CO2 (carbon dioxide ) in the atmosphere that holds heat close to the earth . Ultimately , the heat causes changes in temperatures and weather patterns . While part of the cause of global warming can be attributed to the buildup of CO2 , this simplistic explanation certainly is not the whole story . Our automobiles and other vehicles release carbon dioxide which holds heat in the atmosphere and all living animals and bacteria release CO2 during respiration , so the atmospheric buildup

br of CO2 arises as a result of automobile emissions and animal respiration . By contrast , plants consume CO2 during respiration and release oxygen that animals breath in , so the Greenhouse effect is actually the result of a distortion of the cycle of CO2 and O2 (molecular oxygen ) in the atmosphere

A look at our worldwide deforestation reveals that in the Amazon alone , each year we are losing an area of forestation the size of the state of Massachusetts . Not only is this causing a greater buildup of CO2 in the atmosphere , but it is dramatically altering our global rainfall and weather patterns . Perhaps 25 to 35 percent of the earth 's rainfall occurs over or arises from the Amazon . While we are losing this much tropical forest each year in the Amazon alone , we are certainly losing at least that much or more each year throughout the world due to urban expansion and sprawl , and this dramatically alters the cycle of CO2 and O2 in the atmosphere . Increasing the atmosphere CO2 level increases plant growth , but as we eliminate plants (trees in particular , there are fewer plants to grow faster in response to the increased levels of CO2 in the atmosphere

Carbon dioxide arises from combustion , fermentation and breathing and is consumed by plants . In plants photosynthesis gives rise to O2 whereas in animals the Krebs Cycle gives rise to CO2 . Thus , planting more trees , slowing urban sprawl and reducing combustion that arises from auto emissions are three steps that can combine to reduce atmospheric CO2 . Two of these processes involve either planting trees or slowing deforestation . These steps should reduce CO2 levels by altering the CO2 -O2 cycle

Reference

Krogh , David Krogh (2004 . Biology : A Guide to the Natural World , 3 edition . New Boston , MA : Addison-Wesley

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