claim: Fourth Assessment Report ( AR4 ), in which the likely range is given as 2.0°C to 4.5°C, with a best estimate of 3.0°C ( Pat Michaels )
evidence: In its 2007 Fourth Assessment Report, IPCC said that climate sensitivity is likely to be in the range 2 to 4.5 °C with a best estimate of about 3 °C.