Page "IPCC Third Assessment Report" Paragraph 26

In 2001, the executive branch of the US federal government asked the US National Research Council ( US NRC, 2001 ) to produce an assessment of climate change science.

Part of the assessment by US NRC ( 2001 ) looks at the report produced by Working Group I ( WG I ) in the TAR.

Working Group I's contribution to the TAR assesses the physical scientific aspects of the climate system and climate change.

US NRC ( 2001 ) generally agrees with findings of the WG I report, for example, US NRC ( 2001 ) state that " 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.