REBLOG: Michael Mann says climate models cannot explain the Medieval Warming Period – I say they can’t even explain the present

New climate change article from WUWT.

Watts Up With That?

Ice core data shows CO2 levels changed less than 10 parts per million from 1600-1800 during the MWP.

From the Hockey Schtick:  A new paper from Schurer et al (with Mann as co-author) finds that climate “models cannot explain the warm conditions around 1000 [years before the present, during the Medieval Warming Period] seen in some [temperature] reconstructions.”

According to Schurer et al, “We find variations in solar output and explosive volcanism to be the main drivers of climate change from 1400-1900.” They also claim, “but for the first time we are also able to detect a significant contribution from greenhouse gas variations to the cold conditions during 1600-1800.” This claim is highly unlikely given that ice cores show CO2 levels only changed by less than 10 ppm from 1600-1800, and the effect of 10 ppm CO2 on the climate today remains undetectable even with modern instrumentation.

View original post 317 more words


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