The scientific theory that human activity has lead to an increase in the mean temperature of the Earth. The theory, widely supported by the scientific community, holds that the release of certain greenhouse gases? has caused the increase.

The Intergovernmental Panel on Climate Change is an association of climatologists and planetary scientists studying the climate change. As scientists have learned more and more about the atmosphere and the impact of human activities, the IPCC has released reports in which they have concluded, with a higher and higher degree of certainty, that human activities have had a significant impact on the global climate.

Although the IPCC was created in 1988, it was not until the release of Al Gore's movie, "An Inconvenient Truth" in 2006 that the theory gained widespread acceptance in mainstream America.