We wrote here about a recent effort by a group of climate alarmists headed by geologist Shaun Marcott to resurrect Michael Mann’s discredited hockey stick. The Marcott paper, as you would expect, received uncritical coverage in the liberal press. But it didn’t take long for climate scientists to begin taking it apart, as we noted in our post.
Now Steve McIntyre, who was principally responsible for showing that Mann’s original hockey stick was a fraud, has gone over Marcott’s data on the key proxies he uses for 20th century temperatures, ocean cores. McIntyre found that Marcott and his colleagues used previously published ocean core data, but have altered the dates represented by the cores, in some cases by as much as 1,000 years. Anthony Watts sums up:
It seems the uptick in the 20th century is not real, being nothing more than an artifact of shoddy procedures where the dates on the proxy samples were changed for some strange reason.
McIntyre’s post on his research is here. This chart shows how critical Marcott’s re-dating was to his conclusion that temperatures spiked in unprecedented fashion in the 20th century. The red line shows ocean core temperatures using the original dates under which the data were published: it shows cooling during the 20th century. The black line shows the same data, only with the dates changed by Marcott. It shows temperatures rising significantly, rather than declining: