Demographic perspectives on the rise of longevity

This article reviews some key strands of demographic research on past trends in human longevity andexplores possible future trends in life expectancy at birth. Demographic data on age-specific mortality areused to estimate life expectancy, and validated data on exceptional life spans are used to study themaximum length of life. In the countries doing best each year, life expectancy started to increase around1840 at a pace of almost 2.5 y per decade. This trend has continued until the present. Contrary to classicalevolutionary theories of senescence and contrary to the predictions of many experts, the frontier ofsurvival is advancing to higher ages. Furthermore, individual life spans are becoming more equal, reducinginequalities, with octogenarians and nonagenarians accounting for most deaths in countries with the highest life expectancy. If the current pace of progress in life expectancy continues, most children born this millennium will celebrate their 100th birthday. Considerable uncertainty, however, clouds forecasts: Life expectancy and maximum life span might increase very little if at all, or longevity might rise much faster than in the past. Substantial progress has been made over the past three decades in deepening understanding of how long humans have lived and how long they might live. The social, economic, health, cultural, and political consequences of further increases in longevity are so significant that the development of more powerful methods of forecasting is a priority.