Global life expectancy trends and drivers

Life expectancy rise from 1900 to 2021

Life expectancy has risen dramatically worldwide since 1900. In 1900, the average life expectancy at birth was about 32 years; by 2021 it had more than doubled to around 71 years, with the global average in 2021 just over 70 years. This improvement occurred across all regions and at all ages, not only through reductions in child mortality. The rise is linked to broad advances in health and living conditions, including better nutrition, clean water, sanitation, neonatal care, antibiotics, vaccines, and public health efforts, alongside economic growth and poverty reduction. Although child mortality declines were important early on, recent decades show large mortality reductions across infants, children, adults, and the elderly—meaning death is being delayed rather than only prevented in early life. Life expectancy has also surpassed many historical predictions of a “limit,” with record highs continuing to rise over time. Despite overall gains, life expectancy varies widely between countries and even within countries: for example, in 2021 Nigeria’s life expectancy was about 30 years lower than Japan’s, and lower-average countries often show wider lifespan variation. Women generally live longer than men, but the size of the sex gap changes over time and differs by country, influenced by factors such as war, differences in early-life vulnerability, and adult causes of death (including smoking). Major events like the World Wars, the 1918 Spanish flu, HIV/AIDS, and COVID-19 have left visible marks on mortality and life expectancy trends.

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Role of reduced child mortality

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