Map of life expectancy at birth from Global Education Project.

Tuesday, July 28, 2009

Distinctions and Differences

Whenever scientists air dirty laundry, as Steven Greenberg has done, people get anxious that they will give ammunition to denialists and cranks. Well, they will -- but so will just about anything. The best defense of science, in the long run, is encouragement of self-criticism because that way lies the truth, on which the power of the entire enterprise rests.

So, to be perfectly clear, the question of anthropogenic global warming (AGW) is completely unlike the case of the role of Beta amyloid protein in inclusion body myositis for several important reasons.

1) The community researching IBM is, by comparison, very small and insular. It is subject to almost no outside scrutiny (until now), it rests on a narrow disciplinary base, and it has only a single significant source of funding, the National Institutes of Health. It is not hard to see how such a (metaphorically) incestuous group could develop a premature consensus. AGW, by contrast, is a theory based on the combined efforts of thousands of scientists doing basic research across a wide range of disciplines, in the glaring light of media scrutiny and under unrelenting political challenge.

2) In the case of AGW, there is no alternative set of observations which has been suppressed or ignored. There have been disputes about the validity of some measurements of surface and ocean temperatures over the years, but these were openly aired, investigated, and have been largely resolved. The fact that CO2 concentrations in the atmosphere have been increasing throughout the industrial age, and continue to increase, is not disputed; nor is the warming which has occurred during the past 50 years or so, nor the shrinking of mountain glaciers and arctic sea ice, nor poleward expansion of the historic range of various temperate zone flora and fauna. There is no underlying factual dispute. (Skeptics point out that the rise in average global temperatures appears to have stalled for a couple of years. Nobody denies that, the dispute is over its significance. We are talking about a long-term trend in which year-to-year fluctuations are not important.)

3) There is, at present, no developed theory of the pathogenesis of IBM. Investigators observe that there are abnormalities in muscle tissue accompanied by an inflammatory immune response, but that's about all they know. The presence of Beta amyloid is just an observation, not part of a clear explanatory theory. Were there a convincing theory of IBM, one might be strongly predisposed to choose between the conflicting observations. Since there is not, it would seem the essence of wisdom to look more carefully once again and to determine with greater certainty whether this observation is correct.

In the case of AGW, however, there is a highly developed and compelling theory. We know to a moral certainty why the surface of the earth is warm, while Mars is cold and Venus is blazing hot. It's because our atmosphere is largely transparent to visible and ultraviolet light from the sun, which warms the ground and ocean; they then radiate heat back at longer infrared wavelengths, to which the atmosphere is largely opaque due to the presence of CO2 and vaporous H2O, along with some methane, and so heat gets trapped at the surface. The balance is affected by the concentration of CO2, so more CO2 means warmer temperatures. There are many complications, but that's the basic idea and various testable predictions can be made on that basis. And guess what? The big puzzle pieces fit, numerous predictions in this field have been borne out and so the program of research is productive and continues to provide compelling evidence.

Does that mean there aren't some blind alleys and premature conclusions scattered among the various specific, smaller programs of investigation associated with climate science? Of course not, there probably are some. And over time it will become clear that they aren't paying off. That's how the enterprise works.

I was glad to hear from someone who is living with IBM, who is of course among those who will be most badly disserved if the search for an effective treatment is delayed by a wild goose chase. I confess I didn't know anything about IBM myself so I once again invoked by awesome Googlistic powers and found some background info. This source accepts the Beta amyloid observation without question and suggests it is highly significant, although more technical discussions I have read place much less emphasis upon it. It appears there have been a variety of abnormalities observed in the inclusion bodies, including several abnormal proteins. Clearly there is an a destructive inflammatory process going on but it is not clear why, or what role abnormal proteins may play as trigger or as consequence, if any.

One more thing: Heretical Ideas is a really cool, free online magazine. You might want to start with Alex Knapp's "defense" of the birther movement.

1 comment:

C. Corax said...

Heretical Ideas = Awesome!

Except they're wrong about Loki. I don't give a flying ***k what the comic book says; he's currently bound and suffering pain as a serpent's venom drips onto him. When his wife, who holds a bucket to catch the venom, must turn to empty the bucket and venom drips on Loki, he writhes and we have earthquakes. So I doubt he's in any position to affect the Birther issue.