Theory, Models, and Measurement in Climate Science

One sign that climate science is in a vigorous state is the confluence of rapid developments in theory, models, and measurements. Eli Rabett has emphasized that nothing in climate science makes sense except in the light of theory. This is absolutely true of every mature science. It is the failure to appreciate this point that makes most of the criticisms of evolution, climate science, and other unpopular truths so shallow and worthless.

When I was a young GI I worked with a number of civilian engineers, one of whom tried to point out flaws in evolution to me. His idea of how to do this was to tell me about some site where something supposedly old had been found above strata supposedly much younger. I didn't know much about either biology or geology, but I did know enough to know that his argument was a waste of time. The fact that I knew nothing about the site in question, those who had supposedly investigated it, or what criteria they had used in reaching their conclusions was the least of it. Circumstances sometimes conspire to make an individual site hard to evaluate, but the age of the Earth, and the biological underpinnings of evolution are supported by thousands of concurrent streams of measurement and deductions.

I didn't know it then, but in much of Europe strata have been folded, sheared and contorted so as to produce complex layers where in someplaces a series of layers of rock are overlain by first an inverted version of itself and yet another right side up version on top of that. How do we know that? We know it because a vast number of mutually consistent lines of evidence demonstrate that the northward progress of the African plate crumpled Europe in just that way and because we can see those rocks and strata.

The case for anthropogenic global warming (AGW) is not yet that strong, but it is very strong, and the kinds of arguments that AGW deniers bring forward usually resemble those my engineer friend tried to use against evolution. They pick some isolated set of observations which seem to conflict with theory and push it relentlessly. One of the first such sets was the apparent conflict between global satellite tropospheric temperatures measured by the Microwave Sounder Unit (MSU) and surface based measurements. This was a scientifically important conflict that seemingly could not be explained by either models or theory. Ultimately it was found that the discrepancy was due to a rather subtle mistake in calibration of the satellite measurements.

The infamous hockey-stick is less important scientifically, but notable because denialists turned it into a cause celebre. Briefly, the original hockey-stick paper argued that the current temperature were the warmest in the last 1000 years. A critique claimed that the statistical methodology of the authors wrongly neglected some possibilities which might have allowed temperature comparable to the present about 500 years ago. Subsequent analysis, including some by the National Research Council showed that while the high temps of 500 years ago could not be completely excluded, evidence tended to confirm the hockey-stick. Subsequent analyses have tended to confirm this to me not especially relevant point.

A recent paper appeared to show that the decades long warming trend of the oceans appeared to have halted and reversed a few years ago. This again became the hue and cry of the denialist pack. Now we have found out that this effect too was largely or wholely an artifact due to the deployment of a new type of sensor, which, alas, turned out to have a calibration problem.

The science of AGW is today more comparable to evolution in Darwin's day than our own. Many points remain to be pinned down. Unlike the antidarwinists of a century and a half ago, the anti-AGW advocates have no counter theory comparable to the "intelligent design" idea widely believed before Darwin. It is that lack of a coherent theoretical underpinning that makes their critiques weak and often useless. What they have instead is a group of immensely wealthy interests who wish to delay, halt, and confuse any action to slow anthropogenic emissions.

The denialists are armed with some vague prejudices - the prejudice that "little us" couldn't do real damage to this vast planet and the prejudice that God will take care of us even if we don't take care of ourselves. More reasonably, they believe that real action to end AGW might inconvenience them or require international cooperation and laws restricting corporations.

Aside from that, they have a rapidly shrinking pool of justified doubts and a continually inflated stream of lies, damned lies, distorted statistics and propaganda.