Spray cans and the perils of environmental dissent
Zeal for protecting the environment can easily become intolerance. This seems to have happened with the issue of whether or not to ban chlorofluorocarbon spray can propellants to protect Earth's ozone layer.
Jim Lovelock, a leading British atmospheric chemist, and Michael Allaby, an environmental writer, believe it is premature to rush into such a ban, given the uncertainty of present knowledge about this possible danger. They saw they have difficulty publishing their view.
This is ironic, considering that Lovelock was the first to detect the pressence of chlorofluorocarbons (CFCs) in the atmosphere.
Allaby and Lovelock do not maintain there is no danger. They merely insist that the meteorological threat to the ozone layer and the health hazard of a slight rise in the ultraviolet light reaching Earth's surface due to a reduction in ozone concentration are too unclear to justify a CFC ban at this time. They do not rule out the possible need for such a ban later when more evidence is in.
All scientists concerned with this issue would agree that the evidence is unclear. However, many of them believe it's better to forestall the possible danger now and clear up the uncertainties later. This guilty-until-proved-innocent approach to the issue has prevailed in the United States, where the Environmental Protection Agency has banned CFC propellants.Now the US government is pressuring European countries to follow suit. Allaby and Lovelock object both to the pressure and to the tendency to put regulation ahead of knowledge -- a policy they consider to be based more on fear than on reason.
This is an unpopular position. As Allaby and Lovelock have noted in a letter in Nature: "Our views are hardly revolutionary, but we have had difficulty in expressing them in public. An article [which appeared in New Scientist July 17] has been commissioned from us, so we have no grounds for personal complaint, but an earlier article that had been commissioned was rejected on the advice of American referees and another offer of an article was politely declined. We know of other writers who have experienced similar difficulties in criticising the CFC ban, and we believe that contrary views are being suppressed while truth is dictated by fashion."
Perhaps in the long run, the early CFC ban in the US will prove to have been wise. Or it may come to be seen as a fearful overreaction. What is certain is that suppression of dissenting views on scientific issues is folly. There is no danger urgent enough to justify that.
Allaby and Lovelock have a point when they say, "We fear that by crying 'Wolf!' repeatedly over supposed environmental threats, one day we may not be heard when the threat is real. Indeed, it is a curious fact that amid all the quite genuine threats to the global environment about which we do possess information [such as destruction of tropical jungles, overpopulation, or nuclear war], the purely theoretical threat to the ozone layer is the one that has resulted in legislation."
