claim: His best estimate is that the  warming in response to a doubling of CO2 concentration, which may happen  this century unless the usual suspects get away with shutting down the  economies of the West, will be a harmless 1 Fahrenheit degree, not the 6  F predicted by the IPCC.
evidence: The likely range ( as assessed to have a greater than 66% probability of being correct, based on the IPCC's expert judgment ) is a projected increase in global mean temperature over the 21st century of between 1.1 and 6.4 °C.