Argument: 2001 IPCC report concludes humans causing climate change
- Debate: Is climate change chiefly human-caused? - pro argument.
"There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities." 
Joseph Romm. Book Hell and High Water. 2007. pp 12. - "How strong is the scientific consensus? Back in 2001, President George W. Bush asked the National Academy of Sciences for a report on climate change and on the conclusions of the IPCC assessments on climate change. The eleven member blue-ribbon panel, which included experts previously skeptical about global warming, concluded: Temperatures are rising because of human activities; the scientific community agrees that most of the rise in the last half-century is likely due to increased greenhouse gas concentrations in the atmosphere; and 'the stated degree of confidence in the IPCC assessment is higher today than it was 10, or even 5 years ago.'"