Global Habitability

While human beings are resourceful, it would be foolhardy to gamble the future of clean water supply, secure food sources, and decent health and housing on faith that science and technology will inevitably solve these problems. Technical solutions offer only theoretical promise in the poorest countries where population pressures are most acute, education levels lowest and governments least effective. As Thomas Homer-Dixon has argued, the capacity to adapt and innovate is a human resource that societies and their governments must work to cultivate. Those most overwhelmed by rapid demographic growth and environmental deterioration tend to be least able to invest in education and otherwise adapt to accelerating change.1

Cumulatively, the environmental evidence suggests it will be at best extremely challenging to develop and employ technologies capable of supporting 10 billion human beings on the earth¹s finite supplies of renewable fresh water and arable land. Many policymakers and journalists accept as an authoritative forecast the idea that world population will double by the middle of the next century. This, however, is merely a projection of current trends based on assumptions about birth and death rates that may or may not prove valid as conditions change. As author Joel E. Cohen has suggested, population is now moving into a range where many past analyses have predicted limits to further growth. In much of the world, potential constraints are already evident in the availability of renewable water, cropland, fisheries and forests.2 The worst possible outcome, a slowing of population growth due to rising death rates, remains a possibility.