Mortality in the past – around half died as children

Largely unseen and rarely reported, the deaths of children are a daily tragedy of immense scale. Globally 4.6% of all children die before they are 15 years old; on average a child dies every 5 seconds today.¹

What was the mortality rate in the past? Anthony Volk and Jeremy Atkinson² set out to answer this question. They brought together quantitative estimates on mortality at a young age from a wide range of geographic locations and cultures, going back many centuries.

The authors report mortality rates relative to two different age cut-offs:

– The infant mortality rate measures the share who died in their first year of life.

– The youth mortality rate measures the share who died before reaching “approximate sexual maturity at age 15”.³

Historical estimates of mortality

This visualization shows the historical estimates Volk and Atkinson brought together from a large number of different studies. Shown with the blue marks are estimates of the share of newborns that died in the first year of life – the infant mortality rate. And shown with the red marks you see different estimates of the share that never reached adulthood – what we here refer to as the ‘youth mortality rate’.

Across the entire historical sample the authors found that on average, 26.9% of newborns died in their first year of life and 46.2% died before they reached adulthood. Two estimates that are easy to remember: Around a quarter died in the first year of life. Around half died as children.

What is striking about the historical estimates is how similar the mortality rates for children were across this very wide range of 43 historical cultures. Whether in Ancient Rome; Ancient Greece; the pre-Columbian Americas; Medieval Japan or Medieval England; the European Renaissance; or Imperial China: Every fourth newborn died in the first year of life. One out of two died in childhood.

The available evidence for the mortality rates of children in hunter-gatherer societies and also for our closest relatives – Neanderthals and primates – I summarize at the end of this post.

On the very right of the chart you see the statistics on child health in the world today: The global infant mortality rate is now 2.9%. And 4.6% die before reaching the age of 15.

The global mortality rates over the course of the 20th century are also shown in the chart. Just as recently as 1950 the global mortality rates were five times higher. We have seen a very steep decline during our lifetimes.

The chances of survival for a newborn today are around 10-times higher than the past. But in some countries mortality rates are still much higher than the world average. The country with the highest infant mortality rate is the Central African Republic where close to 9% of all infants die.

The country with the lowest infant mortality rate today is Iceland at 0.16%. The chances of an infant surviving there are 170-times higher than in the past.

Are these high historical mortality rates plausible?

Even on the basis of many dozen studies we only have some snapshots of the long history of our species. Could they all mislead us to believe that mortality rates were higher than they actually were?

There is another piece of evidence to consider that suggests the mortality of children was in fact very high in much of humanity’s history: birth rates were high, but population growth was close to zero.

The fertility rate was commonly higher than 6 children per woman on average, as we discuss here. A fertility rate of 4 children per woman would imply a doubling of the population size each generation; a rate of 6 children per woman would imply a tripling from one generation to the next. But instead population barely increased: From 10,000 BCE to 1700 the world population grew by only 0.04% annually. A high number of births without a rapid increase of the population can only be explained by one sad reality: a high share of children died before they could have had children themselves.

Volk and Atkinson also explain that their historical mortality rates “should be viewed as conservative estimates that generally err toward underestimating actual historic rates”. A first reason is that death records were often not produced for children, especially if children died soon after birth. A second reason they cite is that child burial remains, another important source, are often incomplete “due to the more rapid decay of children’s smaller physical remains and the lower frequency of elaborate infant burials”.⁴

And lastly, we find that a large number of independent studies for very different societies, locations, and times come to surprisingly similar assessments: all point to very high mortality rates for children. For societies that lived thousands of kilometers away from each other and were separated by thousands of years of history, mortality in childhood was terribly high in all of them. The researchers find that on average a quarter of infants died before their first birthday and half of all children died before they reached puberty.

During the last century the global mortality at a young age declined 10-fold

How does the historical data compare with the world today? Globally 95.4% of all children survive the first 15 years of life.

This is a dramatic change from the past. As we’ve seen above: The research suggests that in our long history the chances for a child to survive were about fifty-fifty.

The map shows the mortality up to the age of 15 in every country today. By clicking on any country in this map you see the change over time. You will find that the mortality rate declined in every country around the world.

But you also see that in some parts of the world, youth mortality is still very common. Somalia – on the Horn of Africa – is the country with the highest rate at 14.8%.

And the map also shows the regions with the best health. In the richest parts of the world deaths of children became very rare. In Iceland, the country with the lowest youth mortality, the chances a child survives their first 15 years of life are 99.71%.

The second metric we studied above was the infant mortality rate in the first year of life. Across the historical societies this rate was around a quarter; the global rate today is 2.9%. In our map for infant mortality you find the data for every country in the the world.

Today’s mortality rates of children are still unacceptably high, but the progress that humanity has achieved is substantial. Our ancestors could have surely not imagined what is reality today. And for me this progress is one of the greatest achievements of humanity.