The Island of Doubt

The Economist‘s reputation as the intellectual’s news outlet of choice is probably undeserved — its questionable choice of correspondents and lack of bylines, heavy editing and conservative politics undermine it’s credibility in my book — but because it’s widely read in elite circles, it’s hard to ignore. So the magazine’s feature treatment of climate science is worth looking at. I am pleased to report that, while The Economist may be a straggler when it came to embracing the science, it is now fully on board.

In any complex scientific picture of the world there will be gaps, misperceptions and mistakes. Whether your impression is dominated by the whole or the holes will depend on your attitude to the project at hand. You might say that some see a jigsaw where others see a house of cards. Jigsaw types have in mind an overall picture and are open to bits being taken out, moved around or abandoned should they not fit. Those who see houses of cards think that if any piece is removed, the whole lot falls down. When it comes to climate, academic scientists are jigsaw types, dissenters from their view house-of-cards-ists.

This is to my eyes a fair summary of what divides climatologists from those few who are sincerely skeptical of the broad consensus. And while the magazine doesn’t actually come out and say it, the rest of the feature makes it clear that the house of cards metaphor isn’t really applicable.

Climate science is based on both empirical and theoretical evidence, from many independent lines of inquiry drawn from a wide variety of techniques and technologies. Yes, the satellites could all be wrong about stratospheric temperatures, but then there’s the confirming radiosonde (balloon) data. Yes, the tree-ring data could be problematic, but then there’s foraminfera, and corals and ice cores. Yes, the British CRU temperature records could be biased, but then there’s the US’s NASA and NOAA records, and those of the Japanese. Yes one general circulation computer model might be flawed, but there are dozens of others based on entirely different algorithms. All of these sources point to the same thing: the Earth is warming in accordance with the idea that fossil-fuel emissions are to blame. It’s not a house of cards, but a jigsaw puzzle.

The other thing noteworthy thing about The Economist feature is that in over 4000+ words, the authors(s) include the thoughts of just one dissenting climatologist: Richard Lindzen. His objections, while useful in moving the science forward in the past, have invariably proven incompatible with subsequent discoveries. To the point where he’s no longer considered a serious contributor.

The final words from the feature are also worth reproducing, especially seeing as the length of the piece is likely to deter a lot of blog-habituated readers from getting that far. The issue at hand, what The Economist says is the only major outstanding source of controversy among climatologists, is the range of sensitivity of the Earth to a doubling of atmospheric carbon dioxide levels. That range is widely understood to run from 1.5°C to 4.5°C. If the extreme low end turns out to be close to reality, we will probably be spared most of the negative consequences of climate change. So what does that mean for policy-makers?

Using the IPCC’s assessment of probabilities, the sensitivity to a doubling of carbon dioxide of less than 1.5°C in such a scenario has perhaps one chance in ten of being correct. But if the IPCC were underestimating things by a factor of five or so, that would still leave only a 50:50 chance of such a desirable outcome. The fact that the uncertainties allow you to construct a relatively benign future does not allow you to ignore futures in which climate change is large, and in some of which it is very dangerous indeed. The doubters are right that uncertainties are rife in climate science. They are wrong when they present that as a reason for inaction.

I should think that most of The Economist‘s readers, sophisticated people of finance and politics, would understand that a 50:50 chance of avoiding catastrophe is not very good odds. And only a tiny minority of climatologists believe the chances are that good.