Vallentyne was right: achieving sustainability requires accounting for all relevant factors

Population has waxed and waned as an issue of public consciousness and action by policymakers. The issue is on the ascendancy again in part because of climate change and food crises caused by escalating food prices, the energy crisis and growing shortages of fresh water. In the face of these problems, attempts of some governments to stimulate higher birth rates, over concern with aging populations, are misplaced and counterproductive. Vallentyne's long- neglected 'demotechnic index' holds new promise for considering both population numbers and consumption rates when evaluating the impact of humans on the environment. Its appearance in publication now is all the more important because of the failure of political leaders to act on the numerous expert warnings issued over several decades regarding the impact of human popula- tion growth and expanding utilization of resources. Thus, the world community needs to act urgently to utilize the demotechnic index of Jack Vallentyne to look holistically at ways to achieve a sustainable society.