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Saturday, March 03, 2007


Sunspots and Global Warming - Oh My!

Image Credit Science@NASA

I'm sorry to bang on again about global warming, but as well as astronomy, I'm deeply passionate about science communication, and the public understanding of science. In the 21st century, understanding science is important if we are to have responsible role in civil society (think of the stem cell debate, the debate over genetically modified organisms, how to manage the Murray Darling, whether to stockpile Tamiflu or Relenza against a possible flu epidemic etc.)

The global warming debate, at least as it is being played out in the newspapers, is a familiar one to those of us who have been involved with creationism, anti-vaccination activists and HIV-AIDS deniers. But unlike past encounters, the global warming deniers have full run of the newspapers, with scientists very rarely seen.

The latest installment is the launch of Ray Evans book "Nine Facts About Climate Change". It expands on a pamphlet of the same title released in November 2006. The release was attended by many notables, a fair percentage from the mining industry. Sadly, Liberal MP Dennis Jensen organised the launch on behalf of the Lavoisier group, a global warming denial group set up by by Ray Evans and former mining executive Hugh Morgan. It's unfortunate to see someone sensible caught up in this.

The launch was covered by the Australian and the Age. The Australian also reported part of Former mining executive Arvi Parbo's talk at the launch. What was notable was the absence of any interview or balancing remark for any scientist, let alone climate scientists. The Age's report dryly notes that Mr. Evans's claims are not supported by "scientific bodies including the World Meteorological Organization, NASA, the CSIRO and the Bureau of Meteorology". The Australians report is balanced by an economist talking about the bleak future for coal. An economist! Why were no climate scientists interviewed?

Arvi Parbo said in his speech "I was brought up to believe that scientists not only welcome but encourage questioning of their conclusions." Yes, we do, but when you get the same, debunked questions over and over again we do get a little testy. Having to explain for the nth time that some supposed flaw has been addressed in detail, repeatedly, gets on your nerves after a while. One gets sick of explaining that the HIV virus really does exist, or that there is no connection between MMR vaccine and autism. So it goes for global climate change. The "questions" the "sceptics" ask have been settled a while ago, they just ignore the answers.

Well, what about the book? I haven't read it, but as the book is based on the pamphlet, I am not very sanguine about it. The pamphlet covers the usual denialist territory, and is extensively referenced to well known scientific publications like the Wall Street Journal, and climate expert Christopher Monckton, (that's sarcasm folks). True, it does cite some real scientific papers, but often they are misinterpreted or irrelevant (and pretty much out of date). One issue that illustrates the misinformation best, is a claim the Evans promotes in the pamphlet, and in his launch speech. This the idea that we are going into a cooling cycle. I will assume this cooling claim is in the book as well, in much the same form as the pamphlet, based on how it is mentioned in the speech.

Lets hope the book has a bit better proof reading, the graph the pamphlet claims comes from Badalyan, O. G., V. N. Obridko and J. Sykora, 2001, "‘Brightness of the Coronal Green Line
and Prediction for Activity Cycles 23 and 24"’, Solar Physics, 199, 421-–435
is actually from "Solar Cycles 24 and andand Predicted Climate Response", David C. Archibald, Summa Development Limited, Perth, WA, Australia. This could be a minor typographical error, but the citation of the graph as work of Badalyan et al gives it authority the graph actually lacks (it's from a non-peer reviewed source, unlike Badalyan et al).

The graph is interesting (and here we get to the astronomy content) as it allegedly shows predicted sunspot numbers for solar cycles 24 and 25. As an avid sunspot follower, this graph immediately struck me as odd. I'll come back to this. Evans claims is that in the next decades the world will actually cool, because the next two sunspot cycles will be weak. Now we know that one of the things that drives climate is how much energy the Sun puts out, this is to some degree related to sunspot number. The Maunder minimum, when the Sun was near devoid of sunspots, coincided with the "little ice age". However, the role of less severe fluctuations in sunspot number is not so clear cut. Certainly, climate scientists have spent a good deal of time looking at solar energy variation and its role in the current bout of climate change. The conclusion is that there is little evidence for the sun being responsible for the warming since the 1950's (see also here for further discussion). The latest IPCC summary, based on the latest data, shows a very minimal contribution of solar forcing.

Be that as it may, what about Evans's claims that the Earth will cool in the next few decades. This is based on predictions of the height of sunspot cycles 24 and 25. For cycle 24, the value given by Evans is the lowest of a number of predictions from a variety of predictions (the average prediction is much higher than the one used) , whereas the prediction for cycle 25 appears to be pulled out of a hat.

Sadly for Mr. Evans's prediction, science marches on. The latest predictions, based on far more solid data, is that solar cycle 24 will be bigger than solar cycle 23. Solar cycle 25 is likely to be smaller than solar cycle 24, but again the modern predictions are for a higher cycle than the values used by Evans. The bottom line is that contra Evans, the Earth is not about to go into a cooling cycle anytime soon. This data was publicly and easily available last year, but from Mr. Evan's speech, it looks like he hasn't found it in the process of revising his book from the pamphlet.

Then again, given that the few scientific references that he makes in the pamphlet are mostly from 6-12 years ago, I'm not sure that the book will be up on the latest climate science (this is common with HIV-AIDS denialists, creationists, and anti-vaccination people, they seem to only present the oldest science for their puposes).

In conclusion, even on one easy to check issue, Evans is wrong. This is the only item from the pamphelet that I am sure has made it into the book. However, it appears to be one of Evans major talking points. If something as central and simple as this hasn't been checked, then if the rest of the material in the pamphlet makes it in, the book will be a sorry mix of misinformation and misinterpretation.

This story on the RAS website might interest you.
Yeah, I know of the cosmic ray stroy, it's pretty interesting, and may explain some long term climate events. However, as solar activity doesn't correlate with the current warming since the 1950's, its unlikely to play a major role in the current global warming.
Indeed. Doubtless it'll be one of those things that people latch on to and go "look! see this! humans play no part in climate change!" etc...

I only mention it because (to this layman anyway) it's an interesting take on just one of the many variables that would appear to affect the climate.
I always find the global warming debate interesting. I am admittedly not a scientist, and I have heard both sides of the argument. It would seem to me that both sunspots (especially considering the "Maunder Minimum") as well as CO2 emissions have an effect. It just seems to me climate change has to be complex enough to have many factors.
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