I have been steering clear of Wishart-related material for the last week or two (on the “wrestling with pigs” principle), but I can’t let this post at his blog pass without comment. It begins:
In the climate debate, we can choose to listen to truffle fanciers like Gareth at Hot Topic, journalists like myself or politicians like Al Gore, or one of the leading scientists in the climate field, like Roy Spencer from University of Alabama-Huntsville. The following is a fascinating essay from his blogsite, which backs up the central thesis in Air Con – most of the CO2 increase is natural, not man-made:
He then reposts Spencer’s blog item in full, adding in the comments:
Spencer’s study suggests strong evidence that oceanic CO2 is the primary driver of increased CO2 levels in the atmosphere. (Looking at the graphs, very strong evidence).
Not a squeak out of Hot Topic and no one posting here challenges it.
Notice how a blog post became a “study”? Ah well, here’s a squeak…
Spencer poses this question:
“If warming of the oceans causes an increase in atmospheric CO2 on a year-to-year basis, is it possible that long-term warming of the oceans (say, due to a natural change in cloud cover) might be causing some portion of the long-term increase in atmospheric CO2?”
This is based on a statistical correlation he finds between sea surface temperature and CO2 levels at Mauna Loa (Hawaii) with a six month lag.
Spencer first tried his oceans and CO2 idea out in a blog post earlier this year, and it didn’t go down well — even with his fans amongst the cranks. To Spencer’s credit, he even posted a reply by Ferdinand Englebeen, no climate “alarmist”, patiently explaining why he was wrong. It seems Spencer is now happy to ignore Englebeen (as is Wishart), because the “ocean warming causes the observed CO2 increase” idea is just too attractive.
Unfortunately for Wishart’s “central thesis”, there are three good reasons why this argument just won’t run. The first and most obvious is that we have a very good idea of the amount of fossil fuel that’s been burnt over the last century, and not all of it has shown up in the atmosphere (see Englebeen’s graph here). A large chunk of the carbon we’ve emitted has been absorbed by sinks, of which the largest (by far) is the world’s oceans. To go with that, relatively recent technology allows us to track oxygen level in the atmosphere, and it’s going down. If as Spencer postulates (and Wishart swallows whole) most of the accumulating CO2 in the atmosphere comes from the oceans, then where has all the rest gone?
The second reason is equally straightforward. Over the last century, the ocean has become more acidic — a 30% increase in hydrogen ion concentration (or 0.1pH units) caused by oceans absorbing CO2 from the atmosphere. If the oceans were emitting large amounts of CO2, their acidity would be dropping.
Carbon isotopes provide the clincher, if one were needed. Carbon exists in two common isotopes C12 and C13 (there are others, but much less easy to find). C13 makes up about 1% of all carbon, and about 2% of the atmosphere. Plants prefer to use the lighter (C12) isotope, so fossil fuels and CO2 emitted by plant respiration and decay tend to have more C12. Fossil fuels, being derived from plant materials, are therefore C12 rich, and burning them adds to the C12 in the atmosphere. Careful measurements show that as we’ve burned fossil fuels, so the C12/C13 ratio has shifted to favour the lighter isotope (fuller description here).
There is a fourth objection but it’s not related to the underlying science, rather to the way that science is usually done. Spencer’s thoughts on CO2 have only been published in a blog post at his own web site, and relayed by the crank echo chamber. Roy Spencer is a publishing climate scientist, well able to get material into major journals. If his thesis has any merit, why has he not written it up and submitted it to Nature or Science or Geophysical Research Letters? After all, if he’s right, this is revolutionary, Nobel Prize-worthy material. Why are his thoughts only to be found on Wishart’s blog (and book) and Watts Up With That? Perhaps because he knows that a jury of his peers would reject his ideas for all of the reasons outlined above.
And so back to Wishart. His “central thesis”, based as it is on Spencer’s folly, is clearly wrong. If, as Wishart claims, he has “read the IPCC reports and all the major studies since” then he would understand enough to know where he’s going wrong. But one has to suspect he hasn’t, and clearly doesn’t. Unfortunately you can’t say the same for Spencer.