Global warming theory is the theory that human actions are responsible for the warming trend that has been in progress since the bottom of the Little Ice Age - at about the time of the American Revolutionary War. [1]
Anthropogenic global warming is any increase in global average air temperature caused by human activities.
An assessment panel created by the United Nations is 90% sure that most global warming since about 1950 has been caused by human beings.[1]
The idea that human activities, such as the combustion of fossil fuels, can significantly warm the earth's atmosphere is called the enhanced greenhouse effect.[2]
Relation to current climate change
The anthropogenic global warming theory is one of several explanations for the 1.5 degrees F of warming[3] of the earth's surface recorded since the middle of the 19th century.
The theory enjoys broad based political support from Liberals, Greens and the US Democratic Party, and theory supporters frequently assert the existence of a "scientific consensus" favoring their viewpoint (see Politics of global warming).