The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Greenhouse gases are trace gases in the atmosphere that absorb outgoing infrared radiation from Earth and thereby, like a greenhouse, warm the planet. Naturally occurring greenhouse gases (primarily water vapor and carbon dioxide) make the planet habitable for life as we know it. Anthropogenic greenhouse gases contribute to further warming, referred to as global warming.
Carbon dioxide (CO2) is both a natural and anthropogenic greenhouse gas. Anthropogenic inputs of CO2 mainly from the burning of fossil fuels and deforestation continue to rise, making it the number-one contributor to global warming. Other anthropogenic greenhouse gases include methane (CH4), nitrous oxide (N2O), sulfur hexafluoride (SF6), chlorofluorocarbons (CFCs), and hydrofluorocarbons (HFCs). The last three compounds are synthetic greenhouse gases, which did not exist in the atmosphere before the twentieth century. Molecule for molecule, these gases trap more energy than CO2, but are less abundant in the atmosphere. One molecule of CH4, for example, traps as much heat as twenty-three molecules of CO2. SF6 traps as much heat as 22,200 molecules of CO2.
In 1997 the Kyoto Protocol proposed legally binding restrictions on greenhouse gas emissions, targeting a 5-percent reduction over 1990 levels by 2012. As of December 2001, 186 countries had ratified the protocol. The United States, however, is not one of them.
Turco, Richard P. (1997). Earth under Siege: From Air Pollution to Global Change. New York: Oxford University Press.
U.S. Environmental Protection Agency. "Global Warming." Available from http://www.epa.gov/globalwarming.
United Nations Framework Convention on Climate Change. "Greenhouse Gas Emissions." Available from http://unfccc.int/resource.