“New solar reconstruction paper suggests 6x greater solar forcing change than cited by the IPCC“ (May 10, 2011). Could a paper brought to Anthony Watts’ attention by a hockey stick-obsessed denialist be right? Has it really all just been the Sun’s natural variation? We’re making such a fuss over nothing! Damn those stupid lying climate scientists.

Unfortunately, no. Anthony and his eager associates are conflating, either willfully or through ignorance, amounts of change with rates of change.

Shapiro et. al. (2011) reconstructed “the total and spectral solar irradiance covering 130 nm–10 μm from 1610 to the present” and presented a new model that suggests that TSI (Total Solar Irradiance) may have been “substantially lower during the Maunder minimum than observed today.” But being an actual scientist he also acknowledged that “there is general agreement on how solar forcing varied during the last several hundred years“. Which, surprise, is when man-made global warming happened. Once again, Anthony has toppled the global warming house of cards (not).

Stepping out of Anthony’s narrative for a minute what do the scientists, including Dr. Shapiro, agree upon about Total Solar Irradiance? That global temperatures increased with TSI from 1880 until about 1950. After about 1975 TSI flattens while global temperatures resume their increase. This renewed  global warming (without any help from TSI) is what climate scientists attribute to greenhouse gases (see below, link to Skeptical Science).

Actual TSI vs global temperature. Not a great correlation once greenhouse gases kicked in, huh? Source: Skeptical Science.

Back to Anthony’s narrative: Funny how reconstructions, proxies, and computer models are A-OK with Anthony if he thinks they support the conclusion he wants. Otherwise, the anti-scientific howling is continuous. Hypocrisy much?

Funny how uncertain pre-instrumental records are A-OK with Anthony if he thinks they support the conclusion he wants. Otherwise, the anti-scientific howling is… you can fill in the blanks.

So, perhaps six times as much increase in TSI since 1850? Six times as much sounds huge. The historical TSI fluctuation is around 0.1%, which suggests that the fluctuation may have been up to about 0.6%. However this says nothing about the actual levels of TSI. Those values are neither changed or contested by the paper. If you compare the Figure 2 in Shapiro (2011) with that of  Solanki (2004), shown above, you’ll see that in 1900 Shapiro’s TSI value is 3.9 lower in 1900, and 1.4 higher in 1960. The post-1960 peaks on both the Shapiro (2011) graph and Solanki (2004) TSI graph are the same: 1366 W/m2.

The unfortunate paper authors seem to have done some good refining work on historical Total Solar Irradiance that has minimal impact on the climate change debate but now find themselves falsely held aloft by denialists. I suppose bad publicity is better than no publicity…