For more than a century, human life expectancy climbed steadily. People born in 1900 could expect to live about 62 years, while those born in the late 1930s often reached 80. Now, new research suggests that progress has slowed to the point where future generations may not see the same dramatic gains.
A team of demographers from different renowned institutions analyzed the life expectancy of people born between 1939 and 2000. Their study, published in the Proceedings of the National Academy of Sciences, shows that no matter which forecasting method was used, the outcome was the same: longevity is rising much more slowly than before, and the average person born in 1980 will not reach 100.
The study on life expectancy: Six methods, one result
To test whether life expectancy gains were truly slowing, the researchers relied on data from the Human Mortality Database, covering 23 high-income countries with low mortality rates. They applied six different forecasting approaches, ranging from classic demographic models to newer statistical tools.
Using these models allowed the team to compare projections across multiple perspectives. Some methods looked at population-level mortality patterns over time, while others followed specific birth cohorts throughout their lives. Despite the differences in methodology, all of them pointed in the same direction: life expectancy is no longer climbing at the pace it once did.
In the early 20th century, life expectancy increased by about five and a half months with each new generation. For those born after 1939, that growth slowed to just two and a half to three and a half months, depending on the model. The researchers note that this slowdown is significant, with gains reduced by 37 to 52 percent compared to previous trends.
What slower life expectancy gains mean for the future
The study highlights that life expectancy growth is hitting a ceiling. Earlier increases were fueled by dramatic reductions in infant and child mortality, thanks to improvements in medicine, public health, and living conditions. Today, deaths in young age groups are already rare, leaving little room for further improvement.
While advances in treating diseases among older adults may extend lifespans, the pace of those improvements is not fast enough to replicate the leaps seen in the past. Treatments for cancer, cardiovascular disease, and dementia are progressing, but they tend to add years gradually rather than delivering the dramatic jumps of reduced child mortality.
The authors also stress that forecasts are educated estimates, not certainties. Pandemics, medical breakthroughs, or lifestyle changes could shift future outcomes. But given that six different forecasting methods produced the same result, the conclusion is considered robust. Even if survival rates among older adults doubled relative to current projections, the expected gains would still fall short of the explosive growth seen a century ago.
While life expectancy will likely continue to increase, it will do so at a slower pace than past generations experienced. For societies and individuals, this slower climb means preparing for a future where living past 100 is possible for some, but not the average expectation. The focus will be on improving health quality during the added years we do gain.