Greenhouse Effect

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Global warming is the observed increase in the average temperature of the Earth's near-surface air and oceans in recent decades and its projected continuation. Global warming poses an extraordinary challenge. The world's leading atmospheric scientists tell us that a gradual warming of our climate is underway and will continue. This long-term warming trend poses serious risks to our economy and our environment. It poses even greater risks to many other nations, particularly poorer countries that will be far less able to cope with a changing climate and low-lying countries where sea level rise will cause significant damage.

Relative to the period 1860–1900, global temperatures on both land and sea have increased by 1.4 °F, according to the instrumental temperature record; the urban heat island is not believed to be significant. Since 1979, land temperatures have increased about twice as fast as ocean temperatures. Temperatures in the lowest portion of the earth's atmosphere (troposphere) have increased between 0.22 and 0.4 °F per decade since 1979, according to satellite temperature measurements. Over the one or two thousand years before 1850, temperature is believed to have been relatively stable, with possibly regional fluctuations such as the Medieval Warm Period or the Little Ice Age. Based on estimates by NASA's Goddard Institute for Space Studies, 2005 was the warmest year since reliable, widespread instrumental measurements became available in the late 1800s, exceeding the previous record set in 1998 by a few hundredths of a degree. Estimates prepared by the World Meteorological Organization and the UK Climatic Research Unit concluded that 2005 was the second warmest year, behind 1998 (Wilkipedia, 2006).

Species are disappearing and glaciers all around the world are melting. Animal and plant species have begun dying off or changing sooner than predicted because of global warming, a review of hundreds of research studies contends. These fast-moving...
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