There's ~75 years left in this century and the world average age of death is currently about 70. So this metric would need to increase by 30 years from 2024 to 2100.

@RemNi it can get up to 80 by simply improve access to existing medical technology, but then getting the extra 20 years would require new treatments that are also widely available.

@RemNi but humans born in 2099 will be living to 100+, even if humans born in 1999 are beyond salvage.

Assuming that humans aren't extinct by then, but that's not a 62% likely outcome.

@MartinRandall This question is for the "age of average death" in 2100 right?

@RemNi Is it? It says "start living", not "stop living"

@MartinRandall but then surely the resolution date should be 2200 and not 2100 if that's the logic

@RemNi well, the increment rate of lifespan is around 4 months per year as of now, so even assuming that the increment rate is constant, that means the increment of lifespan would be less than 19-20 years in the following 75 years, indicating that the average lifespan of humans will be around 93-94 years old at most by 2100(the average lifespan of the world was 73.17 years old in 2023).

However, it is unrealistically optimistic to assume that the increment rate will be a constant under the current medical condition, because the fact is, the increment is decelerating, and without a treatment to cure or significantly delay aging, it is expected that the maximal lifespan of average human will be peaked around 85-87 years old, and survival to age 100 years will unlikely to exceed 15% for females and 5% for males at any given point of time after reaching this peak.

Below is the relevant paper pointing out that medical progression is unlikely to extend life without curing or significantly delaying aging:

https://www.nature.com/articles/s43587-024-00702-3

below is an excerpt:

"Over the course of the twentieth century, human life expectancy at birth rose in high-income nations by approximately 30 years, largely driven by advances in public health and medicine. Mortality reduction was observed initially at an early age and continued into middle and older ages. However, it was unclear whether this phenomenon and the resulting accelerated rise in life expectancy would continue into the twenty-first century. Here using demographic survivorship metrics from national vital statistics in the eight countries with the longest-lived populations (Australia, France, Italy, Japan, South Korea, Spain, Sweden and Switzerland) and in Hong Kong and the United States from 1990 to 2019, we explored recent trends in death rates and life expectancy. We found that, since 1990, improvements overall in life expectancy have decelerated. Our analysis also revealed that resistance to improvements in life expectancy increased while lifespan inequality declined and mortality compression occurred. Our analysis suggests that survival to age 100 years is unlikely to exceed 15% for females and 5% for males, altogether suggesting that, unless the processes of biological aging can be markedly slowed, radical human life extension is implausible in this century."

News about this paper by the same person:

https://time.com/7062977/anti-aging-life-expectancy/

Again excerpt:

"Despite all the recent hype from anti-aging evangelists and companies touting ways to extend life, human life expectancy is actually slowing down after accelerating in the previous century.

In a paper published in Nature Aging, researchers led by S. Jay Olshansky, professor of public health at the University of Illinois in Chicago, report that factors that have contributed to remarkable extensions of life expectancy in the 20th century are reaching the point of diminishing returns. Public-health interventions such as clean water and better sanitation and hygiene, as well as medical innovations like vaccines and advances in drug and surgical treatments, are approaching their optimal impact. For human life expectancy to extend much further beyond where it exists today, says Olshansky, entirely new strategies that focus on manipulating the biological processes of aging need to occur. And we aren't there yet."

https://edition.cnn.com/2024/10/07/health/live-span-estimates-wellness/index.html

Again excerpt:

"Gerontologist Jay Olshansky is used to backlash about his views on human longevity. Decades ago he and his coauthors predicted children, on average, would live to only age 85 — only 1% to 5% might survive until their 100th birthday.

Many recoiled from his splash of cold reality, Olshansky said, having grown accustomed to predictions that 50% of babies would live to 100.

“In 1990, we predicted increases in life expectancy would slow down, and the effects of medical interventions, which we call Band-Aids, would have less and less of an effect on life expectancy,” said Olshansky, a professor of epidemiology and biostatistics in the School of Public Health at the University of Illinois in Chicago.

“A lot of people disagreed with us. They said, ‘No, no, NO!’ Advances in medical and life-extending technologies will accelerate and will drag life expectancy along with it,” he said.

Now, 34 years later, Olshansky says he and his coauthors have proven their point. Their analysis of lifespan data from Australia, France, Hong Kong, Italy, Japan, South Korea, Spain, Sweden, Switzerland and the United States was published Monday in the journal Nature Aging.

Overall, female children born in 2019 in these places have a 5.1% chance of reaching 100 years of age, the study said. There is only a 1.8% chance for males.

“We waited 30 years to test our hypothesis. We have shown the era of rapid increases in human life expectancy has ended, just as we predicted,” Olshansky said.

“Now, I want to make sure that this is interpreted correctly,” he added. “We’re still gaining life expectancy, but it’s at an increasingly slower pace than in previous decades.”

Olshansky spoke to CNN about his analysis of longevity data."

Note that Olshansky DOES NOT deny the possibility of curing or significantly delaying aging; instead, he actually actively asks scientists in biology and medicine to find a way to cure or significantly delay aging.

So now here begs the question: can we cure or significantly delay aging in humans in the 21st century?

@MartinRandall your claim that people born in 2099 will have an average lifespan of 100+ is highly improbable if we can't cure or significantly delay aging in humans in the 21st century

@k1234567890y sure, but probably we can.

There will be about 10 billion people at the end of the century. Perhaps the rich will life on average for a 100 years, but never humans on average. And in addition: For every one who dies at 20 by an accident or as soldier someone else would need to be 180 years old.

Humans as in the average world inhabitant?

I would love to be proven incorrect, but the past few years have taught me that any one individual living to be 100, let alone the average person, is an exceptional achievement.

With the increased exposure to unhealth lifestyles; from the processed food we ingest, to the air we breathe, to deadly viruses and bacteria, and the virtual life that has a heavy influence on our mental health. Human life expectancy can only decline by the end of the century. Life expectancy in 2019 had risen to nearly 79 years, but it fell to 77 years in 2020 and dropped further, to just over 76, in 2021. Becoming the largest decrease over a two-year span since the 1920s.

@TafadzwaCarolGuzha Thanks for you valuable information, however I would not agree on that.
Thanks to developments in health, living circumstances, and sanitary rules, life expectancy has improved dramatically throughout the years. In pre-modern era, the average life expectancy was between 30 and 40 years, but it is more than 80 years in some of the countries. Life expectancy in 2019 was over 83 years, especially in countries with higher living standards and affluence such as Switzerland and Australia, with Japan having the longest expectancy at 85 years. On the other hand, despite the shrinking gap in life expectancy between low and high income countries, life expectancy of low income countries has decreased in recent years due to different reasons like war and inconsistency of them. However, in the long run, this scenario is likely to be remedied.
https://fredblog.stlouisfed.org/2021/05/in-poor-countries-no-richer-but-living-longer/
https://www.statista.com/statistics/264719/ranking-of-the-20-countries-with-the-lowest-life-expectancy/
https://ourworldindata.org/life-expectancy
https://www.worlddata.info/life-expectancy.php