Why the Increase in life Expectancy is slowing

This is an excerpt from the Substack of Brian Klaas, an associate professor of global politics at University College London.

       The most significant initial improvement to life expectancy came from the reduction of children who die young. The horrifying chart above makes clear that for most of pre-20th century history, roughly 4 in 10 kids died before they reached their fifth birthday. (It was therefore a relatively typical experience for parents throughout history to bury at least one child).

      The slope of the child mortality line from the mid-20th century to today is a statistical artefact of one of the most gargantuan reductions in human suffering ever achieved.

      Public health interventions and medical advances have also more recently reduced mortality across the aging spectrum, from middle age to the elderly. This provoked the obvious optimism: what if these improvements just keep coming? Are we on an unstoppable scientific quest, that, unlike Gilgamesh’s doomed attempt, could end with extreme longevity if not immortality?

      The problem, as researchers in Nature Aging recently proved, is that the low-hanging fruits have already been plucked. In other words, outside the poorest countries, the knocks to life expectancy that come from the most easily solved sources (such as high levels of childhood mortality) have already been mostly fixed.

      Any significant life expectancy gains would have to come by prolonging life in the elderly who are already reaching the known limits of lifespan. (The Frenchwoman Jeanne Calment, who died in 1997 at the age of 122, is the oldest person to ever live. Despite all the medical advances in the last quarter century, nobody has surpassed that record).2

      After a rapid surge, “since 1990, improvements overall in life expectancy have decelerated.” There are now diminishing returns—and public health provision and medical advances are unlikely to fulfill optimistic dreams of humanity steadily marching toward the longevity of a Greenland shark. There may be an absolute limit of a natural human life.

Brian Klaas is associate professor of global politics at University College London, a contributing writer for The Atlantic, author of “FLUKE: Chance, Chaos, and Why Everything We Do Matters,” and creator/Host of the award-winning Power Corrupts podcast.