I’ve written previously (here and here) about some of the suggestions that climate change and solar activity might be more closely linked than popular global warming wisdom would suggest.
The latest interesting installment can be found at ScienceNow:
To help nail down the effect of solar radiation, geophysicist Mike Lockwood of the University of Southampton, U.K., examined data available since 1955 on the monthly average output of the sun, including sunspots, magnetic activity, and cosmic-ray variations. Then he compared those data, month by month, with average global temperature records, as well as El Niño- and La Niña-induced weather cycles and the atmospheric effects of major volcanic eruptions. The result, Lockwood and colleagues report in two papers published online this week in the Proceedings of the Royal Society A, is that for the past half-century, the sun has exerted only a small influence on climate–about 3% compared with the warming influence of greenhouse gases and natural climate cycles (see illustration).
Lockwood says a key advantage of his approach is that he relied on hard data rather than computer models. “One problem that crops up [in the climate discussion] is that scientists use complex models that nonspecialists don’t understand and therefore don’t trust,” he explains.
The ScienceNow article provides the graphic above, with yellow representing solar output, blue representing El Niño cycles, and grey representing average temperatures.
I’m not sure that I’d take that chart as proof of a lack of correlation. There certainly seems to be some correlation (allowing for random noise, etc.)…but there also seems to be something else at work.
I still have my earlier reservation about studies like this, and global warming (or anti-global-warming) pop science in general — there’s too much politicization of the issue to look at these sorts of reports without discounting the findings due to perceived bias.
I also still think that advocates for making changes to combat global warming would have more success over the long-term if they frame their suggestions with an observation that even if they’re wrong, change is good for other reasons (combating pollution, conservation of resources, etc.)