Benny Peiser last week sent ’round a note on his CCNet list about a study just published by Hai Xu and colleagues from the Chinese Academy of Sciences on the solar-climate link. “New study – Solar Activity is Primary Driving Force of Climate Change” was Benny’s subject line.
The paper wasn’t on line for free, so it took me a few days to swing by the university library and pick up a copy. It was worth it – a very interesting paper, suggesting some tantalizing long-term climate-solar links. But it doesn’t say what Benny and the other climate skeptics who have been so approvingly linking to it seem to think it says.
Xu and his colleagues used oxygen isotopes in peat bogs as a temperature proxy for the last 6,000 years at two sites in China. They compared this with models of solar output over the last 6,000 years and found that “temperature events … correspond well to solar perterubations during the last 6,000 years.” The problem, when I picked up the paper, is that the time scale did not appear fine enough to tease out the temperature increase of the last 100 years, and Xu et al., in the paper’s text, were silent on the question. So I wrote him and asked if he felt their work supported a solar explanation for the warming of the last 100 years. His response:
As you have noticed, because the time resolution of peat deposition (in our study) is not high enough to discuss the dynamic of temperatures on interannual/interdecadal scales, we did not address the cause of the ongoing global warming in the past century.
The paper is “Temperature responses to quasi-100-yr solar variability during the past 6000 years based on delta 18 O of peat cellulose in Hongyuan, eastern Qinghai-Tibet plateau, China,” by Hai Xua, Yetang Hong, Qinghua Lin, Yongxuan Zhu, Bing Hong and Hongbo Jiang, Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 230, Issues 1-2 , 17 January 2006, Pages 155-164
And of course the direct measurements of the last 25 years or so show solar irradiance forcing (averaged over the 11-year solar cycle) to be just .1oC; i.e., not insignificant but not by any means the major factor. See http://ams.confex.com/ams/pdfpapers/74103.pdf, discussion on page 13.
I am rather disappointed to note that you are misleading your readers.
1. “New study – Solar Activity is Primary Driving Force of Climate Change” was Benny’s subject line.
No, it wasn’t. It was: New Study: “Solar Activity is Primary Driving Force of Climate Change” – thus making it clear that I was simply quoting the authors themselves.
2. ‘It doesn’t say what Benny and the other climate skeptics who have been so approvingly linking to it seem to think it says.’
How do you know what I was thinking? You are suggesting that I misrepresented the paper’s findings. But I didn’t comment on the paper at all!
3. ‘The problem, when I picked up the paper, is that the time scale did not appear fine enough to tease out the temperature increase of the last 100 years, and Xu et al., in the paper’s text, were silent on the question.’
I posted extensive excerpts of the paper – rather than just the abstract – in order to show that the paper didn’t focus on or even mention “the temperature increase of the last 100 years.”
In short, none of your implicit accusations are true. The key quote that I highlighted in the Jan 4 CCNet and that provided the subject line was:
“During the past 6000 years, temperature variations in China exhibit high synchrony among different regions, and importantly, are in-phase with those discovered in other regions in the northern hemisphere. Comparisons between
temperature variations and solar activities indicate that both temperature trends on centennial/millennial timescales and climatic events are related to solar variability, suggesting that solar variability is possibly a primary
driving force that influences temperatures.”
Hai Xu et al., Palaeogeography, Palaeoclimatology, Palaeoecology, January 2006
I would welcome it if you could put the record straight.
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Give it up Benny. Your work is fine for the rubes who don’t check work, but not for those who are willing to give your words some scrutiny.
You don’t even know what John was talking about as you are not a CCNet subscriber. I corrected a number of erroneous and misleading statements made on this weblog. Given your ignorance about the subject matter, I doubt that you have anything substantial to contribute to this thread.
Interesting comment Dano. Who do you suppose checked Mann’s work on the “Hockey Stick”? Again, the point of the Hockey Stick debate isn’t whether or not it’s correct so much as the decline in the quality of scientific work, especially concerning the bandwagon of “global warming” – so you’re basically living in a glass house and shouldn’t throw stones.
There’s not much doubt that particulate pollution from China and dust from land use changes settling on the Arctic Ice are decreasing albedo up there, but when we have a topospheric lapse rate basically equal to the thermodynamic lapse rate, it’s obvious the people on the “bandwagon” have trouble adding 2 and 2 themselves. CO2 doesn’t much affect convection.
P.S. I’m not a skeptic when it comes to global warming, I’m an agnostic.