Population, environment, medicine and global sustainability.

The final two decades of this century see our planet in a highly perilous condition. This paper, after touching on the problem of nuclear proliferation, goes on to consider three other issues overpopulation, environmental depredation and the future of medical practice all of which are of high salience. The section on population concentrates on the time required for numbers to stabilize at two children per family. Europe is likely to attain stabilization before 2050, North America and the USSR by 2100. In the developing world South and East Asia could also be in balance by the beginning of the twenty-second century; but the situation in Africa vis-à-vis population growth is much more serious and stabilization cannot be anticipated until about 2150. Destruction of life support systems on a massive scale continues, particularly in developing countries. Much of Asia, Africa and Latin America is riddled with soil erosion; expanding populations of humans and livestock are proving a notable catalyst to desertification; the 'firewood crisis' is deepening as slowly but surely the earth is being deforested. There is little convincing evidence that the major aims of the World Conservation Strategy maintenance and responsible utilization of essential ecological systems, preservation of genetic diversity are being obeyed anywhere in the world. In the more sustainable society of the future engineering medicine with its proclivity for resource depletion will be less attractive. Rather will the emphasis be on prevention and on attempting to delineate the environmental factors known to be responsible for an increasing number of diseases. The likely pattern of morbidity and mortality in the twenty-first century is discussed. Geriatric medicine will hold pride of place; the incidence of cancer will rise markedly, and as an increasing number of Third World nations undergo the process of development diseases, which up till now have mainly affected affluent technological societies, it will spread throughout the planet.