It’s amusing to watch people predict things and then see their predictions fall flat almost before the words leave their mouths.
In 1928, Louis Dublin used US life tables to predict an “ultimate figure of 64.75“, saying that it was impossible for a human to live longer than that without the intervention of “radical innovations or fantastic evolutionary change in our physiological make-up, such as we have no reason to assume”.
He was not aware that at that very moment, non-Māori women of New Zealand had a life expectancy of 74.9 years – more than 10 years more than Dublin thought was possible (see Life Expectancy table here).
8 years later, in 1936, Dublin worked with Alfred Lotka on a reassessment, taking New Zealand’s data into account, and predicted a new limit, 69.93. in 1941, only five years later, women in Iceland broke that limit
The error with this kind of prediction, which people keep on doing over and over, is that it is based on information available on how long we lived in the past, but doesn’t take into account that we are always discovering new ways to live longer.
In 1990, S. Jay Olshansky predicted that “it seems highly unlikely that life expectancy at birth will exceed the age of 85“. In 2002, the life expectancy of Japanese females at birth was 85.2 years.
The country with the current highest life expectancy at birth is Monaco, with an expected life expectancy of 89.5 years.
It should be noted that “life expectancy” is not a limit on mortality. It doesn’t state for a fact, that people will not live longer than that. All it says is that this is the age at which most people are expected to die. There will be outliers that live well beyond that, and accidents where people die before that.
But, the fact that the number keeps on increasing, no matter what the experts say, shows that the human race is (very) gradually winning the fight against mortality.
More recent limits are based not on the past indicators of how long people have lived, but on limitations imposed on the human body by biology itself.
A recent prediction is that the biological limit for human longevity is 126 years old, based on the Hayflick limit, which limits how long a human cell can keep replicating itself, because the telomeres at the end of the DNA shorten each time, until the cells stop replicating and go into senescent mode instead.
But, there is now a treatment that can lengthen telomeres, showing that yet again, the naysayers who put limits on what is possible, are consistently low-reaching. And even for those cells that have passed their Hayflick limits, we have senolytics designed for killing senescent cells.
The future is optimistic. We are pushing our mortality further and further into the future. Read more about how we are learning to solve these problems in my book on how to live forever.