A pair of papers on the relationship between solar variability and climate have been all the rage in the media and climate wars blogosphere over the last week or so.
One, by Foukal et al., got the big headlines: “Study acquits sun of climate change.” Blame the humans! And it was in Nature!
The other, by Scafetta and West, came out a day letter and raised questions about whether climate models are understimating the solar contribution. Sadly, it didn’t get much press (It wasn’t in Nature!), but Benny Peiser gave it a good ride, saying that if Scafetta and West are right, it “would present serious trouble for the IPCC.”
So here’s a quiz for readers. Below the fold are quotes from each of the papers. Try to guess which quote is from which paper:
The first is in a figure caption beneath a graph showing the relationship between a solar temperature reconstruction and actual temperature reconstructions over the last 400 years:
Note the good correspondence of the patterns in particular during the pre-industrial era (1600–1900) and the significant discrepancy occurring in the 20th century with a clear surplus warming. (emphasis added)
The second requires no introduction:
The variations measured from spacecraft since 1978 are too small to have contributed appreciably to accelerated global warming over the past 30 years.
No beer for guessing right. This is just a rhetorical question.
John
Let me answer with a question. Here goes:
Scafetta and West claim that “the sun might have contributed approximately 50% of the observed global warming since 1900.” In other words, they attribute the other 50% primarily to AGW.
According to the IPCC, “most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations.” If that’s the case, most of the observed warming during the frist half of the 20th century – according to Scafetta and West – would have been driven by solar activity. I am just wondering whether the IPCC will be happy to adopt such a position.
Also, according to the IPCC: “Simulations of the response to natural forcings alone (i.e., the response to variability in solar irradiance and volcanic eruptions) do not explain the warming in the second half of the 20th century (see for example Figure 4a). However, they indicate that natural forcings may have contributed to the observed warming in the first half of the 20th century.”