The skeptic argument “It’s the sun” is both the most used skeptic argument and the most visited page on this website. So with NASA GISS updating the surface temperature record with completed 2009 data, I’ve updated the comparison between sun and temperature. While 2009 is the second hottest year on record (tied with 2007), solar activity has fallen to its lowest level in over a century.
To compare sun and climate, the temperature data was taken from the NASA GISS global land-ocean temperature index. To plot Total Solar Irradiance (TSI), I borrowed a technique from Kelly O’Day’s Climate Charts & Graphs. Satellite measurements of TSI only began in 1978 while reconstructions of TSI from sunspot numbers go back to 1611 but end at 2004. As the two datasets show good correlation when they overlap, I’ve used Solanki’s reconstruction from 1880 to 1978 and satellite data from 1979 to 2009.
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