Solar Cycle

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.)

It’s a shame that discussion on global warming, climate change, and conservation have all become so politically charged. Because, frankly, I don’t know whether I’m supposed to trust this sort of news (via Watts Up With That):

The first new sunspot in weeks has emerged today. The spot that has emerged is small and on the equator, so it appears that it is a cycle 23 spot rather than one from the cycle 24 that is gave one spot on January 8th, signaling a start of cycle 24, but has given no cycle 24 type spots since.

Based on what we know about the sun, a cycle 24 spot would be reverse polarity to cycle 23 spots and high latitude. The longer cycle 24 continues to delay producing its spots heightens the concern that we may be in for a longer inactive period on the sun, such as a Dalton type minimum.

In case you’re wondering what a “Dalton type minimum” is, Wikipedia provides this bit of trivia:

The Dalton Minimum was a period of low solar activity, lasting from about 1790 to 1830. Like the Maunder Minimum and Sporer Minimum it coincided with a period of lower than average global temperatures.

There is even a blog dedicated to the prediction of an imminent Dalton-type minimum, entitled “Dalton Minimum Returns.

A recent post there links to a presentation by David Archibald which goes into a bit more detail about such predictions.

Personally, I’m not familiar enough with long-term climatology and the science of global warming to feel comfortable in knowing whether to believe or disbelieve such discussion.

True, I have previously expressed a willingness to believe in global warming, although recent warm years I’d attribute to the effects of other cycles and normal random variation.

However, the idea of cyclical variation of solar activity on the earth’s climate does fit in on my cycles-upon-cycles view of the world.

It would actually be amusingly ironic if human-induced climate change lead to the potential upcoming Dalton-like minimum being not quite as bad as it would otherwise be.

Bah. Now I have a headache from thinking about all these correlations.

Despite that headache, I still think that there are good reasons to pursue conservation and more sustainable technology, beyond the global warming predictions/hype.