In the 1980s the World Health Organization joined other NGOs and government organisations in ceasing to promote ‘indoor residual spraying’ with the insecticide DDT as a method of combating the spread of mosquito-borne diseases, especially malaria. This decision was bad for people living in regions where malaria was endemic, and a triumph for environmental campaigners who had raised fears about DDT's health and environmental effects.
There was a vitriolic controversy about whether this policy was justified. There never was any good evidence that DDT was harmful to the health of humans, and the environmental damage centred on the threat to certain species that were of sentimental and scientific interest. This limited level of potential harm had to be weighed against the fact that malaria was one of the world's leading causes of death and disability of human beings.
And it has remained so. The good news is that the World Health Organization has now reversed its policy on DDT, giving it a clean bill of health and denying that it does any ‘environmental’ damage when used for indoor residual spraying. Most other relevant agencies concur. This is a great victory for those who have been arguing all along that the anti-DDT policy was harmful and had been adopted for essentially frivolous (or as we would put it, religious) reasons. It is a defeat for environmentalist pressure groups which fought bitterly for an almost total ban on DDT. But most of them finally conceded that this was wrong.
SInce the new consensus is that DDT, used carefully, is not environmentally dangerous after all, the issue of how much environmental damage is worth how much human suffering and death is now mercifully relegated to theoretical status as far as DDT policy is concerned. But it does, in general, remain an urgent moral issue, and one that is hardly addressed in the political arena. As part of the critical debate about the current environmentalist consensus, should we not also be debating past policy? How much unnecessary suffering was caused by the policy that the WHO and environmental pressure groups have now reversed?