Nuclear thaw - re-examination of nuclear-winter hypothesis

BEGINNING IN 1983, much was heard about the likelihood of a "nuclear winter" if large-scale nuclear war should ever break out. According to this notion, which was advanced by various "scientific spokesmen," vast clouds of waste material would block the sun's rays; the extreme formulations asserted that this would lead to human extinction.

Many of those who earlier propagated this view have now pulled back. Climatologists and astrophysicists have been re-examining the nuclear-winter hypothesis, and the consensus, expressed in conferences and articles, has now shifted against any extreme scenario. The estimates now seem to converge on a lowering of the global temperature by about ten degrees.

Related to the earlier wild speculation about a nuclear winter was another theory, now largely discredited, to the effect that the dinosaurs died because a large meteor hit the earth, filling the air with debris; as the sun's rays were blocked, the reptiles froze. The evidence that has emerged against this is compelling. The dinosaurs became extinct over too long a period of time for the theory that this was a preview of nuclear winter to be plausible.

Which leads us to a reflection on "science" and what it allegedly "says." Even the educated public has little idea of what real science actually is, and what its limits are. It is a method that involves precise measurement, careful observation, analysis, and repeatable experimentation. The assertions of a scientist must be subject to refutation. If they are in some realm beyond refutation they are meaningless from a scientific point of view.

Science has always been politicized to some degree, but quite possibly never more so than in our own day. In the instance of nuclear winter and the dinosaur theory, an educated guess would be that the "scientists" were more moved by the vast and emotional campaign against the deployment of the Pershing II missile than by anything that can properly be called science.

Beware, tehn, when "spokesmen" for "science" make spectacular speculative claims, whether about the ozone layer or about oat bran. Real science is not where Barnums like Carl Sagan operate.