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A storm in a polder? Or a water tower?

The Dutch Environmental Assessment Agency, PBL, has released the results of a minutely detailed search for errors in part of the second volume of the Fourth Assessment of the Intergovernmental Panel on Climate Change. The search focussed on the eight chapters that assessed regional impacts.

It turned up quite a number of errors, mostly too trivial to waste time over, but two of them glaring. One was about how much of the Netherlands is below sea level. The IPCC gave a wrong figure, 55%. A quarter is much closer to the truth. But in the words of the PBL, “the error was made by a contributing author from the PBL[!], and the [IPCC Coordinating Lead Authors and Lead Authors] are not to blame for relying on Dutch information provided by a Dutch agency.” Really? My atlas shows land below sea level in a tasteful strawberry shade, so I would have thought that a glance at the atlas would make it seem unlikely that more than half of the Netherlands is below sea level. On the other hand, the Dutch have had their finger in the dyke for centuries, and so are unlikely to be misled for long by anything the IPCC, or for that matter their own government, says on this point.

The other error was about the water tower of Asia, but I don’t want to revisit that one just now other than to repeat that blunders happen.

This is all so predictable, and in a cosmic sense so trivial. There is, however, a way to view these blunders in proper perspective, even though I know I shouldn’t use the word “paradigm” in an article for popular consumption.

All of us in the sciences know what a paradigm is, because we have either read or been told about Thomas Kuhn’s 1962 book The Structure of Scientific Revolutions. A paradigm is a big, governing idea, one that makes sense of a lot of other ideas that would be disparate without it. Kuhn argued that when a scientific discipline undergoes a revolution, it is actually undergoing a paradigm shift, in which an old paradigm is replaced by a new one.

I am not sure about the old paradigm. Kuhn says that a paradigm is a set of one or more past achievements that some scientific community acknowledges for a time as supplying the foundation for its further practice. The achievements have to be unprecedented enough to attract adherents, and open-ended enough to leave all sorts of unsolved problems for them to work on. I detest the relativistic sociology of “acknowledges for a time”, but this paraphrase is important as a key to understanding the recent fusses about climatic change and IPCC mistakes.

I don’t think there ever was an old paradigm in the atmospheric and neighbouring sciences. First of all, there has been no revolution. Climatologists have been doing what Kuhn calls “normal science” for centuries. The foundations in dynamics and thermodynamics are as they have been since the 17th century, and in radiation as they have been since the late 19th century. But atmospheric and oceanic dynamics, and radiative physics, describe systems that, though they change continually, always stay the same unless you mess with them.

In fact, the big unifying idea didn’t burst onto the scene. It evolved. Fifty years ago and more, there weren’t many “adherents” in the study of global environmental change because there was little to adhere to other than a vague idea that another Ice Age ought to begin any millennium now. But there is certainly something to adhere to today. These days, the big unifying idea is the greenhouse effect, and in particular the anthropogenic greenhouse effect. It unifies because it is triumphant at explaining the facts while generating more questions than it answers.

Denialists are fond of criticizing climatological claims that “The science is settled”, or equivalently that “The debate is over”. If any climatologists have ever used those particular words, then what they meant to say was that the paradigm is doing fine. It did not originate in a revolution, but it has adherents who see it as unprecedentedly successful and find it so open-ended that the science of climatic change is still growing explosively.

If you can find a big enough concept, like Kuhn’s paradigm, even mistakes about Asian water towers and Dutch polders fall into intellectual place. They are storms in a teacup. Debate about Himalayan glaciers and the risk of flooding in the Netherlands will go on indefinitely, enlivened by the occasional howler. If and when something more intellectually powerful comes along, we will replace the paradigm, but for now it is firmly in place and there is no sign of a replacement.

Posted by Graham Cogley on July 26, 2010 3:00 PM | Permalink