The real cause of climate change over the last millennium

via Tallbloke’s Talkshop
http://ift.tt/1WIzElD

Fig 1. Integration of solar data departing from long term average as a proxy for OHC

OK, this the last post before I go. This is a comment I made this morning over at Pierre Gosselin’s place (awaiting approval at time of writing this).

To understand the effect of solar variation on a large heat capacity mass like Earth’s oceans, you have to integrate the solar data to get a reasonable proxy for ocean heat content. If you look at empirical comparisons of average sunspot number during periods when the ocean temperature is steady, you can derive a value of approximately 40 sunspots per month. This also happens to be the average sunspot number over the period of record from 1749 to today. Integrating the sunspot numbers as a running total departing from this average produces a reasonable proxy for OHC.

Calibrating the Steinhilber et al TSI reconstruction based on 10Be to the same baseline, we obtain a reconstruction which compares well to the Mann et al 2008 millennial temperature reconstruction, as seen in Fig1.

Adding in the detrended AMO and PDO oceanic oscillations and a CO2 value giving around 0.4C per doubling as per Richard Lindzen’s estimate, we obtain a curve which reproduces HADSSTv3 to an R^2 of 0.9 for monthly values since 1870 in Fig 2.

Fig 2. Combining the solar integral with detrended AMO, PDO, and CO2 at 0.4C/doubling to replicate HASsst3 (lower panel)

The continuation of the model in blue in the lower panel is based on our planetary solar model plus a replication of the AMO from the C20th. It shows a moderate drop in global SST to 2050.