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: Without feedbacks the radiative forcing of approximately 3.7 W / m2, due to doubling CO 2 from the pre-industrial 280 ppm, would eventually result in roughly 1 °C global warming.