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: Scenario B1 Best estimate temperature rise of 1.8 °C with a likely range of 1.1 to 2.9 °C ( 3.2 °F with a likely range of 2.0 to 5.2 °F ) Sea level rise likely range [ 18 to 38 cm ] ( 7 to 15 inches ) Scenario A1T Best estimate temperature rise of 2.4 °C with a likely range of 1.4 to 3.8 °C ( 4.3 °F with a likely range of 2.5 to 6.8 °F ) Sea level rise likely range [ 20 to 45 cm ] ( 8 to 18 inches ) Scenario B2 Best estimate temperature rise of 2.4 °C with a likely range of 1.4 to 3.8 °C ( 4.3 °F with a likely range of 2.5 to 6.8 °F ) Sea level rise likely range [ 20 to 43 cm ] ( 8 to 17 inches ) Scenario A1B Best estimate temperature rise of 2.8 °C with a likely range of 1.7 to 4.4 °C ( 5.0 °F with a likely range of 3.1 to 7.9 °F ) Sea level rise likely range [ 21 to 48 cm ] ( 8 to 19 inches ) Scenario A2 Best estimate temperature rise of 3.4 °C with a likely range of 2.0 to 5.4 °C ( 6.1 °F with a likely range of 3.6 to 9.7 °F ) Sea level rise likely range [ 23 to 51 cm ] ( 9 to 20 inches ) Scenario A1FI Best estimate temperature rise of 4.0 °C with a likely range of 2.4 to 6.4 °C ( 7.2 °F with a likely range of 4.3 to 11.5 °F ) Sea level rise likely range [ 26 to 59 cm ] ( 10 to 23 inches ) Both past and future anthropogenic carbon dioxide emissions will continue to contribute to warming and sea level rise for more than a millennium, due to the timescales required for removal of this gas from the atmosphere.