Future

The U.S. Census Bureau view on the future of longevity is that life expectancy in the United States will be in the mid-80s by 2050 (up from 77.85 in 2006) and will top out eventually in the low 90s, barring major scientific advances that can change the rate of human aging itself, as opposed to merely treating the effects of aging as is done today. The Census Bureau also predicted that the United States would have 5.3 million people aged over 100 in 2100. The United Nations has also made projections far out into the future, up to 2300, at which point it projects that life expectancies in most developed countries will be between 100 and 106 years and still rising, though more and more slowly than before. These projections also suggest that life expectancies in poor countries will still be less than those in rich countries in 2300, in some cases by as much as 20 years. The UN itself mentioned that gaps in life expectancy so far in the future may well not exist, especially since the exchange of technology between rich and poor countries and the industrialization and development of poor countries may cause their life expectancies to converge fully with those of rich countries long before that point, similarly to the way life expectancies between rich and poor countries have already been converging over the last 60 years as better medicine, technology, and living conditions became accessible to many people in poor countries. The UN has warned that these projections are uncertain, and cautions that any change or advancement in medical technology could invalidate such projections.^[25]

Recent increases in the rates of lifestyle diseases, such as obesity, diabetes, hypertension, and heart disease, may eventually slow or reverse this trend toward increasing life expectancy in the developed world, but have not yet done so.

Scientist Olshansky examined how much mortality from various causes would have to drop in order to boost life expectancy and concluded that most of the past increases in life expectancy occurred because of improved survival rates for young people. He states that it seems unlikely that life expectancy at birth will ever exceed 85 years.^[26]

However, since 1840, record life expectancy has risen linearly for men and women, albeit more slowly for men. For women the increase has been almost three months per year. In light of steady increase, without any sign of limitation, the suggestion that life expectancy will top out must be treated with caution. Scientists Oeppen and Vaupel observe that experts who assert that "life expectancy is approaching a ceiling ... have repeatedly been proven wrong." It is thought that life expectancy for women has increased more dramatically owing to the considerable advances in medicine related to childbirth.^[27]

Mice have been genetically engineered to live twice as long as ordinary mice. Drugs such as deprenyl are a part of the prescribing pharmacopia of veterinarians specifically to increase mammal lifespan. A large plurality of research chemicals have been described at the scientific literature that increase the lifespan of a number of species.

Some argue that molecular nanotechnology will greatly extend human life spans. If the rate of increase of life span can be raised with these technologies to a level of twelve months increase per year, this is defined as effective biological immortality and is the goal of radical life extension.