Brendan Shaw
“… when famine, epidemic, migration and state failure are joined by further forces of disruption, like climate change, …. decline can turn into disastrous, centuries-long collapses and dark ages”
- Ian Morris, Why the West Rules – For Now, 2010
For most of human history, people have lived around about 30 years. It’s only in the last 150 to 200 years that human life expectancy has increased to the levels it has today.
Things like growing wealth, greater investment in public health, relatively more peace, and scientific advances have all contributed to humans today living the longest they have since we first came down out of the trees.
Trends in life expectancy around the world
After loitering around 25 to 30 years for thousands of years, during the 19th century average world life expectancy started to rapidly increase. Some countries led the charge, particularly those that quickly industrialised and saw substantial economic growth through the Industrial Revolution.
With some variation, many countries have seen their life expectancy increase by about 30 years from the mid-19th century to today.
Source: Our World in Data. ‘Life Expectancy’, https://ourworldindata.org/life-expectancy, accessed 21/3/2023.
A person living today can expect to live 71 years on average. The ‘average’ bit is important because while most countries have seen their peoples’ life expectancy increase by about three decades over the last 150 to 200 years, life expectancy varies quite a lot between those countries with the longest average life expectancy and those with the shortest.
For example, countries including Japan, South Korea, Australia and Switzerland can typically expect their people to live 82 to 83 years on average. Other industrialised and high-income countries tend to score highly as well.
Source: Our World in Data. ‘Life Expectancy’, https://ourworldindata.org/life-expectancy, accessed 21/3/2023.
At the other end of the scale, lower-income countries in regions such as Africa typically show a much lower life expectancy. While many of these countries have also seen their average life expectancy increase by over 30 years, their life expectancy is still well below high-income countries. Compared to those countries with the highest life expectancy of over 80 years, countries like Ethiopia and South Africa have an average life expectancy of 62 years.
Source: “Life Expectancy”, Our World in Data, Global Change Data Lab, University of Oxford, https://ourworldindata.org/life-expectancy#world-maps-of-life-expectancy-in-1800-1950-and-2011-max-roserref, accessed 2/3/2023.
So, while the extension of our life span over the last two centuries is perhaps one of our greatest success stories as a species, the 20 year gap in life expectancy that still exists between the richest and poorest countries shows that we still have a lot of work to do.
Things like improving education and income, achieving peace and stability, reducing communicable diseases and better tackling non-communicable or chronic diseases like heart disease, diabetes and cancer in poorer countries will go a long way to closing this life expectancy gap.
Forces of disruption affecting national life expectancy
Ian Morris is one of my favourite historians. His quote above about the forces that have disrupted societies throughout human history – things like famine, epidemics, migration, state failure and environmental problems like climate change – all show up in the life expectancy charts for individual countries and regions.
The experiences of individual countries tell the story. Be it the impact of plagues and epidemics on the United Kingdom during the 17th century, the catastrophic impact of World War II in Europe and Japan, the mid-1980s famine in Ethiopia, or the HIV outbreak in South Africa at the end of the 20th century, all of these disruptions to society affect a country’s life expectancy.
A few individual country examples show the impact of different major disruptions to society that affect life expectancy.
Source: Our World in Data. ‘Life Expectancy’, https://ourworldindata.org/life-expectancy, accessed 21/3/2023.
The substantial drops in life expectancy seen in countries like Afghanistan, Ethiopia, Japan, South Africa, Spain and Syria coincide with events such as wars, pandemics, famines and failures in public policy or state failure. One can almost plot a country’s life expectancy against significant moments in time in a country’s history.
What did Covid-19 do to life expectancy in countries?
For my lectures to masters students on global health trends, every year I update this chart on world life expectancy from Our World in Data for the students.
This year, for the first time, the impact of the Covid-19 pandemic has become apparent in the world life expectancy figures.
The most recent data available for 2021 shows a decline in average life expectancy in many countries and regions around the world because of Covid-19. While probably an artefact of the comprehensive data collection seen today compared with probably any other point in history, the impact of Covid-19 on worldwide life expectancy is obvious.
Average global life expectancy dropped from 72.8 years in 2019 prior to the pandemic to 71 years by 2021.
Source: Our World in Data. ‘Life Expectancy’, https://ourworldindata.org/life-expectancy, accessed 21/3/2023.
For my students, it’s proof that so far as global health is concerned, they are living through an historic period.
And it’s obvious to see why. When you look at the official Covid-19 global death figures from the WHO against the pre-pandemic causes of deaths worldwide in 2019, the human toll of Covid-19 compared to other diseases is obvious to see. The official figures report that as at early March 2023, almost 7 million people worldwide have died from Covid-19. Comparing against the leading causes of worldwide deaths prior to the pandemic, Covid-19 in 2022 became the second most important killer in 2022 after ischaemic heart disease.
Source: WHO. 2020. “The Top 10 Causes of Death”, 9 December, Fact Sheet, https://www.who.int/news-room/fact-sheets/detail/the-top-10-causes-of-death, accessed 6/3/2021; WHO, "WHO Coronavirus (COVID-19) Dashboard", https://covid19.who.int/, accessed 6/3/2021.
We know also that the official reported figures almost certainly vastly under report the actual total deaths worldwide. Projections by the Economist and John Hopkins University using excess death numbers estimate that around 20 million people have so far died from Covid-19.
Source: Our World in Data, https://ourworldindata.org/excess-mortality-covid?country=IND~USA~GBR~CAN~DEU~FRA, accessed 2/3/2023.
Just as other wars, failed government policies, famines and pandemics in countries have triggered declines in their life expectancies, so too Covid-19 has led to reductions in life expectancy.
While historians will be looking back at the impacts of Covid-19 on society for decades to come, the data are already showing that we live in historically significant time.