Factors Affecting Global Warming
From Thermal-FluidsPedia
Various mechanisms affect the severity of global warming to different degrees. Among the mechanisms that increase the rate of global warming are:
1. Rising temperatures cause acceleration in the rate of decay of organic matter, producing methane, a major greenhouse gas.
2. Rising temperatures make forests drier and more vulnerable to pests, diseases, and fire. For example, it is estimated that by doubling of the carbon dioxide levels in the atmosphere, will raise earth’s surface temperature by about 3 C; the US alone will lose up to 40% of its forests (2).
3. With rising temperatures, the Arctic permafrost and tundra will melt and release an enormous amount of methane into the atmosphere, accelerating global warming. Tundra and permafrost cover about one-fifth of all land.
4. Oceans are huge sinks of carbon dioxide. The solubility of water is highly temperature dependent -- the colder its temperature, the higher the capability of water to dissolve carbon dioxide. As ocean temperatures rise, some of the stored carbon dioxide is released back into the atmosphere.
While most mechanisms act to amplify global warming, there are some that reduce the effect. Among the mechanisms responsible for reducing the rate of global warming are:
1. The burning of fossil fuel releases particles that act as condensation nuclei and increase cloud-cover, blocking sunlight from reaching the earth.
2. Higher temperatures increase rates of ocean water evaporation, thereby expanding low altitude cloud-cover (a). The role of clouds in global warming is particularly complicated as clouds differ in thickness, composition; they can travel and may or may not result in rain. More water vapor contributes to increased blanketing effects, both to keep the reradiated terrestrial radiation in (positive effect), and incoming solar radiation out (negative effect). Clouds net contribution in heating or cooling the atmosphere is not certain.
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References
(1) Toossi Reza, "Energy and the Environment:Sources, technologies, and impacts", Verve Publishers, 2005
(2) Cline, William R. 1992. “The Economics of Global Warming,” Washington D.C. Institute for International Economics
Additional Comments
(a) The decrease in solubility of carbon dioxide with temperature is also the main reason that soda, beer, and other carbonated beverages become flat shortly after they are opened. Soda cans are filled under pressure. When opened, their pressure drops to atmospheric levels. Carbon dioxide is less soluble and leaves the beverage. Similarly, when the beverage warms up, its ability to dissolve carbon dioxide reduces and the beverage goes flat.
Further Reading
Gore, A., An Inconvenient Truth, Penguin Books, 2007.
Roleff, T., Pollution: Opposing viewpoints, Greenhaven Press, 2000.
Walsh, P. J., Dudney, C. S., Copenhave, E. D., Indoor Air Quality, CRC Press, 1984.
Environmental Science and Technology, published by the American Chemical Society.
External Links
Environmental Protection Agency (http://www.epa.gov).
Occupational Safety and Health Administration (OSHA) (http://www.osha.gov).
Intergovernmental Panel on Climate Control (IPCC), (http://www.ipcc..ch).
United Nations Environment Programme (http://www.unep.org).
World Health Organization (WHO) (http://www.who.ch).