It would be hard to overstate the impact of medical and public health innovations over the last 200 years. Back in 1800, nowhere in the world had a life expectancy above age 40. In 1900, wealthy nations were faring better, but the global average life expectancy was still around 32. By 2021, however, the global average life expectancy had more than doubled to 71. How did this happen?
For starters, it’s important to note that life expectancy has already been fairly high in wealthy countries for decades. In 1950, developed nations like the U.S. and Canada, most of Western Europe, and Japan all had life expectancies above 60. The entire continent of Africa, meanwhile, had an average life expectancy of 36. What has increased the global life expectancy so significantly has also been shrinking this gap.
Poverty reduction and medical advancements have played key roles in this progress. Globally, we’re in an era of plenty: more people than ever before have access to quality food, clean water, antibiotics, vaccines, and other life-saving items. Public health efforts have supported better sanitation in developing nations, and extreme poverty levels have drastically declined. All of this has meant both significantly lower infant mortality rates and a higher life expectancy at every age after that worldwide.
Of course, life expectancy still varies considerably. For one, women tend live longer than men across the board, though the differential varies from country to country. The data seems to suggest that women are more likely to survive at every stage: newborn girls are less susceptible to viruses and genetic disorders than newborn boys; adult women are much less likely to die from “external causes of death,” like accidents and violence; and in old age, they don’t get sick or die from their illnesses as often as men do (likely due to less risky lifelong health behaviors).
The gap in life expectancy between wealthy and poorer countries persists as well, though not to the same extent. In 2021, Monaco had the highest life expectancy of any country at around 85.9. The lowest, meanwhile, was in Chad, with an average life expectancy of around 52.5. Within nations, there are also often big differences in life expectancy. Especially in countries with lower life expectancies, poorer and more rural populations tend to have significantly less healthcare access and, as a result, live much shorter lives than the rest of the country.
The United States stands apart from the other richest countries in the world in one depressing way: an abnormally low life expectancy. In fact, whereas life expectancy has been increasing in the vast majority of the world, it actually declined in the United States between 2014 and 2019—even before the COVID-19 pandemic caused a global life expectancy drop. In 19 U.S. counties, life expectancy is even below the global average.
Experts have pinpointed various reasons why U.S. life expectancy is so low: chronic health issues like smoking and obesity, comparatively high homicide and suicide rates, the opioid epidemic, car accidents, economic inequality (leading to relatively high rates of infant and maternal mortality), and lack of access to healthcare all play a part. Importantly, many of these factors lead to the deaths of young people. They thus strongly impact life expectancy across the whole population.
Yet maximum life expectancy continues to exceed expectations and delight scientists. For decades, experts have been theorizing about the highest possible average life expectancy. In 1928, for example, Dublin published a study guessing that it would be 65 (not knowing that New Zealand had already surpassed that number). Now, estimates are more likely to be in the 90s. But on average, it’s about five years before a maximum life expectancy prediction is surpassed—so only time will tell how far we can go, and how long we can live.