All of us in politics remember the famous headline “It’s The Sun Wot Won It”, from April 11th 1992, when the Conservatives squeaked a narrow and unexpected victory from the jaws of defeat. But change just two letters, and you have an interesting comment on the current climate debate: “It’s the Sun Wot Dun It”.
On Friday, the day of the solar eclipse, there were widespread reports that the temperature dropped as the Sun was temporarily occluded, and it struck me that this was a telling confirmation of the obvious — that the primary driver of global temperature and climate is the Sun. You might think that this observation, which I Tweeted, was so blindingly obvious that no confirmation was necessary. But there are those who believe that the earth’s complex and chaotic climate system can be reduced to a single factor — and that that single factor is an odourless, harmless, non-toxic, invisible trace gas amounting to 0.04% of the atmosphere. (Although CO2 is of course important — CO2 is vital for live on earth — and the current level is very low in geo-historical terms. Indeed if it were halved overnight — as I’m sure Al Gore would love to do — plants would struggle to grow, and we’d struggle to eat).
Nonetheless I thought my Tweet was timely, topical and relevant, and an opportunity to draw attention to one of those self-evident facts that is, nonetheless, occasionally lost sight of.
I was therefore fairly astonished when my usual retinue of Twitter trolls went into overdrive to draw attention to my “scientific illiteracy”. Better yet, the Huffington Post ran a headline “Helmer says eclipse proves that the Sun is heating the earth”? This after I had received an e-mail from HuffPost Journo Jessica Eglot asking me to “explain my Tweet”.
Jessica, please get your facts right. I did not claim that the eclipse “proved” anything. I merely pointed out that the rapid cooling the moment the Sun was obscured clearly illustrated the importance of solar radiation in maintaining the Earth’s climate. And that, surely, is beyond dispute. Of course if the Sun were not heating the earth, then the terrestrial temperature would be close to absolute zero, and we’d all be dead.
But perhaps the trolls who accuse me of “scientific illiteracy” should do a bit of science themselves, rather than taking their environmental theories straight from that noted scientist Al Gore (or Railway Engineer Ravendra Pachauri). They could start by reading Professor Fritz Vahrenholt’s book “The Neglected Sun” . Vahrenholt by the way started out as a green socialist politician, became an Environment Minister, and ended up as CEO of RWE’s major renewables business “Innogy”.
The fact is that there is a rather good correlation between solar activity and climate — and a rather poor one between CO2 levels and climate. Particularly striking is the fact that the two particularly cold periods of the Little Ice Age , the Maunder and Dalton Minima, occurred when the Sun was exceptionally inactive (in sunspot terms). And as Vahrenholt remarks, the Sun appears to be entering a new quiet phase, which could presage a new cooling period.
More generally, there has been a 1000-year cyclical pattern of mean global temperature for at least ten thousand years, and arguably longer. The slight warming we have seen in the last 150 years is entirely consistent with that pattern — we need no anthropogenic explanation. For those who believe that industrial CO2 emissions are driving temperature, they have a problem explaining what drove earlier warm periods long before the Industrial Revolution.
Of course leaving aside the eclipse, solar irradiance is actually rather consistent, which is why the IPPC feels justified in ignoring it. But work by Svensmark and others has shown that the solar magnetic field (closely linked to sun-spot activity) is highly variable, and appears to affect the cosmic ray flux reaching the Earth. This in turn affects cloud formation, albedo and climate.
If we leave aside the effects of nuclear decay in the Earth’s core, the Sun is the source of practically all energy on earth. Even fossil fuels are “fossilised sunlight”, while bio-fuels are last season’s sunlight. If you choose to believe that a trace gas (actually less significant than water vapour in terms of its greenhouse effect) is more important in determining the Earth’s climate than our friendly neighbourhood Star, you’re free to do so. But it’s an odd idea.