Madam, - In his recent article on acid rain (March 6th), Prof William Reville says that "acid rain was succeeded by the 'hole in the ozone layer' as the next environmental worry, which in turn was pushed off the stage by global warming. . .before global warming we briefly worried about global cooling. . .You'd have to wonder."
This seems to suggest (perhaps with tongue in cheek) that concerns about the ozone layer, and about global warming, could prove baseless. Coming as it does from the UCC public awareness of science officer, the suggestion should not go unchallenged.
In the first instance, concerns about the ozone layer were not groundless. They were not "pushed off the stage" by the issue of global warming, but by a radical and effective solution to the problem - a global reduction in the use of CFCs.
As regards global warming, there is now a broad consensus of expert opinion around the world that climate change is a very real threat (and very likely due to human causes). This consensus is not invalidated by a small number of studies carried out in the 1970s, for the simple reason that much of today's analysis is based on evidence that was not available 30 years ago.
Finally, it should be pointed out that earlier predictions of "global cooling" are often overstated in the media. In reality, the key hypothesis at the time was that the global climate might be an unstable system that could be easily perturbed - a hypothesis that is proving to be all too accurate. - Yours, etc,
Dr CORMAC O'RAIFEARTAIGH,
Waterford Institute of Technology.