Comment from “Sean” Harvard Graduate Climatologist from

I am a climate scientist, and it is clear that the evidence that “human activity is prominent [sic] agent in global warming” is NOT overwhelming. The repeated statement that it is does not make it so. Further, even if we accepted the hypothesis, cap-and-trade legislation does not do anything about it.
Here are the facts. We have known for years that the Mann hockey stick model was wrong, and we know why it was wrong (Mann used only selected data to normalize the principal component analysis, not all of it). He retracted the model. We have known for years that the Medieval Warm period occurred, where the temperatures were higher than they are now (Chaucer spoke of vineyards in northern England). Long before ClimateGate it was known that the IPCC people were trying to fudge the data to get rid of the MWP. And for good reason. If the MWP is “allowed” to exist, this means that temperatures higher than today did not then create a “runaway greenhouse” in the Middle Ages with methane released from the Arctic tundra, ice cap albedo lost, sea levels rising to flood London, etc. etc.), and means that Jim Hansen’s runaway greenhouse that posits only amplifying feedbacks (and no damping feedbacks) will not happen now. We now know that the models on which the IPCC alarms are based to not do clouds, they do not do the biosphere, they do not explain the Pliocene warming, and they have never predicted anything, ever, correctly. As the believers know but, like religious faithful, every wrong prediction (IPCC underestimated some trends) is claimed to justify even greater alarm (not that the models are poor approximations for reality); the underpredictions (where are the storms? Why “hide the decline”?) are ignored or hidden. As for CO2, we have known for years that CO2 increases have never in the past 300,000 years caused temperature rise (CO2 rise trails temperature increase). IPCC scientists know this too (see their “Copenhagen Diagnosis”); we know that their mathematical fudges that dismiss the fact that CO2 has not been historically causative of temperature rise are incorrect as well. We have also known for years that the alleged one degree temperature rise from 1880 vanishes if sites exposed to urban heat islands are not considered. We have long known that Jones’s paper dismissing this explanation (Jones, et al. 1990. Assessment of urbanization effects in time series of surface air temperature over land, Nature 347 169- 172) is wrong and potentially fraudulent (see the same data used to confirm urban heat islands in Wang, W-C, Z. Zeng, T. R Karl, 1990. Urban Heat Islands in China. Geophys. Res. Lett. 17, 2377-2380). Everyone except Briffa knows that the Briffa conclusions are wrong, and why they are wrong; groups in Finland, Canada (lots of places actually) show cooling by this proxy, not warming; the IPCC even printed the Finn’s plot upside down to convert the fact (cooling) into the dogma (warming).
(Link to entire article)