Changes

[[Image:Composite antarctic NASA.jpg|thumb|right|250px|A composite map of [[Antarctica]] showing areas of greatest warming in red, other colors indicate cooling. The Wilkins Ice Shelf lies off the peninsula in the top left corner, and shows extensive warming. Overall, Antarctica shows more cooling than warming, especially in the east, the area to the right.]]

[[Image:Composite antarctic NASA.jpg|thumb|right|250px|A composite map of [[Antarctica]] showing areas of greatest warming in red, other colors indicate cooling. The Wilkins Ice Shelf lies off the peninsula in the top left corner, and shows extensive warming. Overall, Antarctica shows more cooling than warming, especially in the east, the area to the right.]]

'''Global warming''' theory asserts that changing gas content in the atmosphere is increasing the temperature of the world by changing the ability of heat to escape the atmosphere. Some gases attributed with causing this effect are produced by industrial and power plants, while many others come from natural phenomena. In addition to atmospheric gas content, many other factors control the earth's temperature, which has its own pattern of heating and cooling.

'''Global warming''', scientifically speaking, is a worldwide increase in atmospheric temperature. Such increases have alternated with periods of global cooling throughout geological history in regular, natural cycles. Many political activists use the term '''"global warming"''' to refer the anthropogenic global warming theory (AGW), which asserts that human activity such as spewing "[[greenhouse gases]]" is causing more temperature increase than all natural causes combined.

 

While many climate scientists have insisted that man-made pollution has caused dangerous warming, some computer models designed to predict long term trends fail to predict recent short-term cooling that the Earth is experiencing. <ref>[http://online.wsj.com/article/SB125686509223717691.html Earth Cools, and Fight Over Warming Heats Up, Wall Street Journal, 2 November 2009]</ref> Because 1998 was the year of El Nino, a natural phenomenon that occurs intermittently and causes the year in which it occurs to be anomalously hot, the relation of that year to longer trends is unclear. As temperatures have been falling since 1998, increasing doubt is being cast on the validity of global warming claims.  

In November 2009, emails were stolen that demonstrated wrongful manipulation and concealment of data by scientists who have insisted that there is dangerous man-made global warming, leading the organization whose e-mails were released to provide clearer peer review evidence supporting their earlier claims.

In November 2009, emails were stolen that demonstrated wrongful manipulation and concealment of data by scientists who have insisted that there is dangerous man-made global warming, leading the organization whose e-mails were released to provide clearer peer review evidence supporting their earlier claims.