A commenter named RobW at Deltoid has pointed out that Alexander Cockburn has joined the ranks of global warming denialists with an article on the Counterpunch site. Now I haven’t been reading it much lately but I used to read Counterpunch quite a bit, and in fact still have a current subscription. I don’t agree with everything there, and have no problem with that, but this article strays beyond matters of opinion.
Cockburn starts with some comments about carbon trading and comparing it with those who payed the Catholic church to absolve their sins. I’ve seen a comparison like this before, I believe it was in New Internationalist in their issue on carbon offsets. In that case there was a valid point to be made, there are many issues surrounding carbon offset schemes that are of concern and valid criticisms to be made, but Cockburn applies this comparison to anyone concerned about their carbon footprint. He justifies this by claiming that there is no scientific basis to anthropological global warming. How does he reach this conclusion? Well, throw away that nice new IPCC report, it’s all rubbish because Alexander Cockburn knows a guy who spent 3 years as a meteorologist who said that humans don’t cause global warming. OK, he showed him a graph too. Unfortunately we don’t have the privilege of seeing this graph, but he does at least describe it to us (has he heard of the saying “a picture paints a thousand words”?).
The graph in question compared industrial output with atmospheric CO2 concentrations. We aren’t given a source for this graph, in particular where the measurements come from. Reliable C02 measurements started in the late 50s with Mauna Loa, so I’m immediately suspicious of measurements from the depression era. Cockburn does mention earlier measurements coming from ice cores, so my best guess is that he was looking at something like this. I would question how accurately you could resolve trends over such small time periods with this data. In fact, his description of how smoothly the C02 concentration rises makes me suspect that he is looking at something like this data which has been smoothed using a spline fit. Of course, without knowing his source this is speculation, but I don’t know of any data from pre-Manau Loa which gives the sort of accuracy that he seems to be describing. You can compare with this graph of industrial emissions and decide whether it is the devastating critique that he claims it is.
Especially in light of the fact that the human contribution to atmospheric CO2 concentration is supported by the mix of carbon isotopes in the atmosphere.
Next he brings up the old claim that because there’s so much more water in the atmosphere, then it must be more important to global warming than CO2. This has been dealt with here.
Next is the claim that because there was more CO2 in the Eocene period when there weren’t cars then that is some sort of problem for the AGW theory. This relies on such an obvious fallacy that I barely feel the need to address it. So his claim is that since CO2 has been at higher levels in the distant geological past, then the increase must be natural now, despite the fact that we’ve been digging up fossil fuels out of the ground and burning them at a furious rate for the past 100 years or so. To imply that this is some sort of embarrassing secret swept under the carpet by climate scientists is ridiculous.
He then throws in some unsubstantiated claims about the medieval warm period, once again implying that it requires subterfuge on the part of “greenhousers” to deal with, you can get the real story from Coby Beck.
He brings up the lag between temperature and CO2 in ancient glacial cycles as if it is a recent development, however it has long been understood. It was recently dealt with on Real Climate, but note the link back to a post from 2004 on the same topic. The claim that the current climate trend is due to Milankovitch cycles seems to be based purely on the idea that a CO2 increase must be due to some naturally caused warming. I know of no credible claims that the Milankovitch cycles should be currently causing warming, unless he thinks that we are warming after the little ice age – but this can’t be attributed to the cycles either.
Finally there is a bizarre mention of the heat from the Earth’s core. It reminds me of the fellow (whose name escapes me) who used to post on various blogs (such as Deltoid) about how the dominant influence on climate was the heat from the core. I’ll leave it as an exercise to the reader to work out where that theory goes wrong. Anyway, I’m not suggesting that Cockburn subscribes to this theory, but I have no idea why he brought it up. It seems to be part of some sort of appeal to incredulity thrown in for good measure.
So overall, some guy with dubious qualifications in climate science (“a lifelong mistrust of climate modeling”) claims that the vast majority of working climate scientists are wrong, and Cockburn uses it as a basis to insult all those who are concerned about climate change as gullible fools.
Update: Real Climate have written about this as well now.
Update II: Cockburn vs Monbiot.