31 Mar '13, 8pm

Commentary on Marcott et al #ExtendedHockeyStick study continues in the comment thread of new #RealClimate article:

Commentary on Marcott et al #ExtendedHockeyStick study continues in the comment thread of new #RealClimate article:

A: Maybe. We cannot exclude the possibility that some of the paleotemperature records are biased toward a particular season rather than recording true annual mean temperatures. For instance, high-latitude proxies based on short-lived plants or other organisms may record the temperature during the warmer and sunnier summer months when the organisms grow most rapidly. As stated in the paper, such an effect could impact our paleo-reconstruction. For example, the long-term cooling in our global paleotemperature reconstruction comes primarily from Northern Hemisphere high-latitude marine records, whereas tropical and Southern Hemisphere trends were considerably smaller. This northern cooling in the paleotemperature data may be a response to a long-term decline in summer insolation associated with variations in the earth’s orbit, and this implies that the paleotemperature proxie...

Full article: http://www.realclimate.org/index.php/archives/2013/03/res...

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Response by Marcott et al.

realclimate.org 31 Mar '13, 1pm

A: Maybe. We cannot exclude the possibility that some of the paleotemperature records are biased toward a particular seaso...