“Greenhouse gases are accumulating in Earth’s atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise. Temperatures are, in fact, rising.

"The IPCC's conclusion that most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations accurately reflects the current thinking of the scientific community on this issue.”

National Academy of Sciences, Climate Change Science (2001)

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"Warming of the climate system is unequivocal."

Intergovernmental Panel on Climate Change, Climate Change 2007: The Physical Science Basis (2007)