Enlightenment Now: The Case for Reason, Science, Humanism, and Progress

Look at the numbers on the vertical axis: they refer to the percentage of children who die before reaching the age of 5. Yes, well into the 19th century, in Sweden, one of the world’s wealthiest countries, between a quarter and a third of all children died before their fifth birthday, and in some years the death toll was close to half. This appears to be typical in human history: a fifth of hunter-gatherer children die in their first year, and almost half before they reach adulthood.⁷ The spikiness in the curve before the 20th century reflects not just noise in the data but the parlous nature of life: an epidemic, war, or famine could bring death to one’s door at any time. Even the well-to-do could be struck by tragedy: Charles Darwin lost two children in infancy and his beloved daughter Annie at the age of 10.

Figure 5-2: Child mortality, 1751–2013

Sources:Our World in Data, Roser 2016a, based on data from the UN Child Mortality estimates, http://www.childmortality.org/, and the Human Mortality Database, http://www.mortality.org/.

Then a remarkable thing happened. The rate of child mortality plunged a hundredfold, to a fraction of a percentage point in developed countries, and the plunge went global. As Deaton observed in 2013, “There is not a single country in the world where infant or child mortality today is not lower than it was in 1950.”⁸ In sub-Saharan Africa, the child mortality rate has fallen from around one in four in the 1960s to less than one in ten in 2015, and the global rate has fallen from 18 to 4 percent—still too high, but sure to come down if the current thrust to improve global health continues.

Remember two facts behind the numbers. One is demographic: when fewer children die, parents have fewer children, since they no longer have to hedge their bets against losing their entire families. So contrary to the worry that saving children’s lives would only set off a “population bomb” (a major eco-panic of the 1960s and 1970s, which led to calls for reducing health care in the developing world), the decline in child mortality has defused it.⁹

The other is personal. The loss of a child is among the most devastating experiences. Imagine the tragedy; then try to imagine it another million times. That’s a quarter of the number of children who did not die last year alone who would have died had they been born fifteen years earlier. Now repeat, two hundred times or so, for the years since the decline in child mortality began. Graphs like figure 5-2 display a triumph of human well-being whose magnitude the mind cannot begin to comprehend.

Just as difficult to appreciate is humanity’s impending triumph over another of nature’s cruelties, the death of a mother in childbirth. The God of the Hebrew Bible, ever merciful, told the first woman, “I will multiply your pain in childbearing; in pain you shall bring forth children.” Until recently about one percent of mothers died in the process; for an American woman, being pregnant a century ago was almost as dangerous as having breast cancer today.¹⁰ Figure 5-3 shows the trajectory of maternal mortality since 1751 in four countries that are representative of their regions.

Figure 5-3: Maternal mortality, 1751–2013

Source:Our World in Data, Roser 2016p, based partly on data from Claudia Hanson of Gapminder, https://www.gapminder.org/data/documentation/gd010/.

Starting in the late 18th century in Europe, the mortality rate plummeted three hundredfold, from 1.2 to 0.004 percent. The declines have spread to the rest of the world, including the poorest countries, where the death rate has fallen even faster, though for a shorter time because of their later start. The rate for the entire world, after dropping almost in half in just twenty-five years, is now about 0.2 percent, around where Sweden was in 1941.¹¹

You may be wondering whether the drops in child mortality explain all the gains in longevity shown in figure 5-1. Are we really living longer, or are we just surviving infancy in greater numbers? After all, the fact that people before the 19th century had an average life expectancy at birth of around 30 years doesn’t mean that everyone dropped dead on their thirtieth birthday. The many children who died pulled the average down, canceling the boost of the people who died of old age, and these seniors can be found in every society. In the time of the Bible, the days of our years were said to be threescore and ten, and that’s the age at which Socrates’s life was cut short in 399 BCE, not by natural causes but by a cup of hemlock. Most hunter-gatherer tribes have plenty of people in their seventies and even some in their eighties. Though a Hadza woman’s life expectancy at birth is 32.5 years, if she makes it to 45 she can expect to live another 21 years.¹²