U.S. Period Life Expectancy
U.S. Period Life Expectancy
Experts expect U.S. life expectancy to reach 83 by 2050.
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Our Analysis
How do we interpret these results
Period life expectancy in the U.S. was about 79 years in 2023, and all three groups expect steady gains that widen under the rapid AI progress scenario. The unconditional median climbs to 81 to 83 years by 2050 (experts 83, public 81, superforecasters 82) and 85 to 88 years by 2100 (experts 88, superforecasters 87, public 85). Under the rapid AI progress scenario, the 2100 median rises to 95 years for experts and roughly 90 for the public and superforecasters. However, there is disagreement, especially in the long-run tails. For example, under the rapid AI progress scenario in 2100, 25% of experts forecast below 88 years and 25% forecast above 105.
Forecasts by scenario
Median forecasts from experts for each scenario
| scenario | 2050 | 2100 |
|---|---|---|
| Unconditional | 83 yrs | 88 yrs |
| Moderate Progress | 83.8 yrs | 90 yrs |
| Rapid Progress | 86 yrs | 95 yrs |
| Slow Progress | 81.6 yrs | 85 yrs |
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* Denotes non-overlapping bootstrapped confidence intervals between group aggregates.
Rationale analysis
The main lines of reasoning driving the spread in estimates
Distribution of the gains
Almost all forecasters foresee period life expectancy rising over the two time horizons, but many are pessimistic that the gains will be either exceptional or widely shared: “AI-accelerated medicine mostly raises a ceiling the rich already enjoy, and if AI widens inequality it could drag the floor further.”; “My optimism for AI benefits being spread across the economic spectrum is fairly low, reflected in my predictions and higher upper tails.” Optimists tend to expect gains will be widely shared: “AI is directly addressing the top sources of mortality (and others e.g. transport accidents) in ways that are likely to be broadly accessible, and so I don’t think economic inequality will hold it back.”
Human behavior as the bottleneck
Optimists typically expect that AI, particularly in a rapid scenario, will lead to “accelerating the development of new and better treatments” and that this will extend lifespans. Many pessimists don’t view access to treatments as the key consideration: “It’s lifestyle choices, and it’s a lot to ask of technology to salvage the livers, kidneys, and pancreata of those pushing the curve down.”; “The things actually killing Americans early are behavioral and social, not waiting on a lab. Obesity, deaths of despair, overdoses, gun deaths.”
The trendline
Optimists and pessimists typically anchor their predictions on an extrapolation of the historical trendline but differ in what additional factors—beyond AI—they think will bend the trendline up or down. Optimists often point to the potential for the U.S. to catch up to other developed countries, along with an existing-drug tailwind: “Switzerland is already at [84]. [The] US just needs to get closer to the frontier!”; “OWID indicates that some of the leading countries have greatly exceeded the US in life expectancy…Monaco and San Marino: 86.4 years and 85.7 yrs respectively.”; “The U.S. is already on a path toward improvement because of GLP-1s and related metabolic drugs.” Pessimists tend to view the trend as having already flattened—“[The] U.S. has stagnated for the better part of two decades while peer countries kept climbing”—and likely to stay flat given U.S. lifestyle choices and “constrained…healthcare access.”
Accounting for catastrophic and existential risk
Some pessimists use their 10th percentile forecasts (elicited for the unconditional and rapid scenarios) to account for catastrophic and existential risk, with a handful even entering zero as a value: “There's more than a 10% chance that humanity goes extinct.” Optimists tend to judge such risk as unlikely—“I find it far more likely that AI will provide far more beneficial outcomes than pose existential risk to mankind that could cause some type of widespread health crisis, war or other activity that would significantly lower average life expectancies”—or, in a few cases, to exclude it on methodological grounds: “Not really pricing in p(doom) since extinction resolves ambiguously.”
A biological ceiling
Pessimists often see a hard limit to potential lifespans: “Extending life expectancy from 70 to 80 was easier than extending to 90 will be, AI or no AI.”; “~90 years is really pushing the limits of [the] normal human body.” A few optimists express skepticism such a ceiling exists: “Aging itself might be slowed a lot, or maybe even solved. If that happens, some people could live around 200 or longer, and the average could rise much more than most people expect.”
Rationale examples
High-quality rationales from forecasters across the range
Pessimists
The positive channel is largely offset by four negative channels, so the median rises only modestly even under Rapid. Positive: AI-driven medical advance (drug discovery, faster trials, early detection). Negatives: (1) [financial] inequality [leading to] widening health disparities (per the background’s top-5% vs bottom-5% divergence); (2) physical-task automation reducing daily physical activity, rising lifestyle-disease (cardiovascular, type-2 diabetes, obesity) risk; (3) ‘deaths of despair’ drug/alcohol mortality, which the COVID natural experiment showed rise sharply and quickly under reduced human interaction even when suicide does not; (4) social isolation from reduced human interaction.
I absolutely believe that wealthy, disciplined, highly educated people are going to get much better health care over the next several decades. They will have better diagnostics, better cancer screening, better metabolic drugs, better cardiovascular prevention, better personalized medicine, better sleep, better food, better exercise environments, less physically destructive work, and much faster access to anything that looks even vaguely life-extending. Some of them are going to be walking around with full-body scans, continuous biomarkers, concierge doctors, AI health agents, personalized nutrition, early-stage disease detection, and a suspiciously serene ability to “prioritize recovery” while other people are still eating lunch from a gas station because their second job starts in 43 minutes and they still have 4 deliveries to make out of their 14 year old hatchback. That is not a small effect, but it is also not the same thing as moving the national average dramatically…The average gets dragged around by obesity, diabetes, cardiovascular disease, overdose deaths, suicide, alcohol, violence, chronic stress, environmental exposure, poor access to primary care, crappy diets, medical debt, [and] rural hospital closures…
Many countries, currently, and with currently available technology, have life expectancies as much as 7 years beyond the US. Those levels are achievable without any AI boost…[it is] public policy that enable[s] or prevents those improvements.
AI, while [it] may indeed unlock novel cures for disease and the secret to life extension, it also may contribute mightily to deaths of despair if people lose their jobs, sense of self, and sense of community. Curing disease will matter little if half the nation decides to drink itself to death.
Optimists
The rise of precision medicine and cancer therapy, sharp declines in cardiovascular mortality, improved air quality especially as a result of the rise of electric cars, and improved social security would contribute to such improvement.
If we got 100 years of scientific progress in 10, then we could see ~100 years of trend life expectancy gains ([in] 5-10 years). There’s also a chance of some kind of more fundamental breakthrough that leads to a new trend (escape velocity etc.)
In the rapid world, if aging genuinely becomes an engineering problem and the major killers—cancer, cardiovascular, neurodegenerative—get solved or managed, you can run well past anything in the historical record.
The biggest [AI-driven] improvements will come with safety benefits. Activities that are risky now, including driving, will become dramatically safer, reducing untimely deaths and increasing lifespan[s]. These safety improvements, combined with incredible advances in health sciences, will dramatically increase lifespan[s].