And these lying, cheating alarmists have the gall to hurl vile abuse at those who challenge them.
Lewis tells me that the latest observational estimates of the effect of aerosols (such as sulfurous particles from coal smoke) find they have much less cooling effect than thought when the last IPCC report was written. The rate at which the ocean is absorbing greenhouse-gas-induced warming is also now known to be fairly modest. In other words, the two excuses used to explain away the slow, mild warming we have actually experienced – culminating in a standstill in which global temperatures are no higher than they were 16 years ago – no longer work.
In short: we can now estimate, based on observations, how sensitive the temperature is to carbon dioxide. We do not need to rely heavily on unproven models. Comparing the trend in global temperature over the past 100-150 years with the change in “radiative forcing” (heating or cooling power) from carbon dioxide, aerosols and other sources, minus ocean heat uptake, can now give a good estimate of climate sensitivity.
The conclusion – taking the best observational estimates of the change in decadal-average global temperature between 1871-80 and 2002-11, and of the corresponding changes in forcing and ocean heat uptake – is this: a doubling of CO2 will lead to a warming of 1.6-1.7C.
This is much lower than the IPCC’s current best estimate, 3C.