As several of the papers in this special issue show, environmental health hazards are currently most prevalent in developing countries at the household level. Among the commonest hazards are indoor air pollution, arsenic and infectious agents in drinking-water, and local environmental exposure to lead. Finding ways to reduce these risks more quickly remains an important item on the global agenda because of the significant burden of disease they impose.
At the United Nations Conference on the Human Environment in 1972, much of the concern was about chemical contaminants, the depletion of natural resources, and urbanization. This reflected problems resulting from rapid industrialization in the West and the Soviet bloc countries, as well as uncontrolled agricultural and industrial expansion in the newly independent developing countries. Earlier there had been serious episodes of air pollution, such as the London fog of 1952, organic mercury poisoning in Minamata, Japan (disclosed in 1956), accumulations of heavy metals (especially lead and cadmium), pesticide toxicity, and exposures to environmental ionizing radiation. Similar toxicological hazards persist today. Since 1972, we have had the major accidents of Bhopal, Seveso and Chernobyl, and it is highly probable that there will be more.
Meanwhile, a further set of large-scale environmental problems has emerged and moved towards centre-stage. They add up to the conviction that we are living beyond the Earth's means, and that the continued increase in human numbers and economic activity poses a serious problem for the world as a whole. In September 1999 the United Nations Environment Programme (UNEP) issued its Global environment outlook 2000, whose final chapter begins as follows.
"The beginning of a new millennium finds the planet Earth poised between
two conflicting trends. A wasteful and invasive consumer society, coupled
with continued population growth, is threatening to destroy the resources
on which human life is based. At the same time, society is locked in a
struggle against time to reverse these trends and introduce sustainable
practices that will ensure the welfare of future generations." (1)
The report urges all national governments to recognize the urgent need for concerted and radical action in order to make the transition to a sustainable system.
Some of the health implications of living in a destabilized global ecosystem are reviewed in this issue. They include the impact of climate change on vector-borne diseases (Githeko et al., pp. 1136-1147), the health effects of El Nino (Kovats, pp. 1127-1135), and the challenge of protecting health in a time of rapid change (Woodward et al., pp. 1148-1155).
The sustainability transition involves ensuring that the natural ecological, geophysical and chemical systems that support life on Earth can continue to function. The aim here is for those alive today to meet their own needs without making it impossible for future generations to meet theirs. To do this we have to bequeath to them a biosphere that is intact. …