Daily Archives: March 23, 2013

Regional Marcott

We’ve already examined the big picture of global temperature according to the recent reconstruction for the holocene (in particular the last 11,300 years) from Marcott et al. We also took a close look at the recent uptick in temperature. Now let’s see about some of the regional differences indicated by these data.

In their supplemental materials, Marcott et al. included the reconstructions restricted to three very wide latitude bands: the northern extratropics (from 30N latitude to the N.Pole), the southern extratropics (from 30S latitude to the S.Pole), and the equatorial band (from 30S to 30N latitude). These reconstructions are computed using their “Standard 5×5” method. But we noted that they may suffer from a difficulty, that as time marches forward, the drop-out of more and more proxies can lead to spurious jumps in the average temperature. This is especially difficult for the most recent time period, because that’s when there are the fewest proxies remaining (so things are less accurate anyway) and there’s more proxy drop-out.

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