‘Nuclear winter’

Press, 10 July 1987, Page 16

‘Nuclear winter’

Sir, — I feel that Neil Cherry’ does climatology a disservice by perpetuating the claim that “nuclear winter” is fact (July 4). The theory is based on a computer model produced by an amalgam of mathematicians and an astronomer (Carl Sagan). As such, the mwel is fraught with

uncertainties and questionable assumptions. It assumes considerable upper atmosphere contamination along a similar mechanism to volcanic eruptions. Not all nuclear blast clouds reach so high and the smoke from the fires resulting is unlikely to escape the troposphere which, as the unfortunate recipients of acid rain are aware, is an extremely efficient scrubber of aerosols put into it from elsewhere. Stage 1 geography tells that such a dust cloud as envisaged by this model can have a very different effect over the sea to that over land. The sea would very likely heat up and cause violent rainfall events over the land. Even should the sea not be heated up, if the Earth’s surface cools considerably the ocean is a very efficient heat reservoir and circulation systems and precipitation would restore a normal climatic balance readily. The above effects have been monitored in the aftermath of volcanic eruptions. My real gripe over the “nuclear winter” issue is that when one questions its validity as a model, one is seen as supporting nuclear war. But such a misuse of science damages the anti-nuclear cause. — Yours, etc., A. P. NICHOLS. July 5, 1987.