Sunday 13 January 2013
Right and wrong
Here's an odd bit of deja presque vu: in an earlier post I noted how Wm McBride got it right on Thalidomide but wrong on Debendox. Paul Crutzen was one of the three 1995 Nobel Prize-winners for his work 20+ years earlier on ozone depletion. He showed that nitrous oxide generated by soil bacteria was stable and long enough lasting to reach the stratosphere where it could be converted to nitric oxide by UV photolysis. Nitric oxide (as any fule kno) then goes on to strip one of the Os from ozone. Crutzen suggested in 1970 that piling nitrogenous fertilizers onto the corn-fields of the Midwest would substantively increase the stratospheric nitric oxide burden. That's all copacetic. The following year he pointed the finger of shame at supersonic airliners as another significant destroyer of ozone. This turned out to be wrong on two counts: a) supersonic airliners never became economic enough or popular enough to replace subsonic planes: only a dozen Tupolev Tu-144s and a few more Concordes were ever built and b) as NOAA boffin David Fahey calculated in 1995, even 500 such supersonic planes would only drop the ozone concentration by 1-2%.