There is nothing more banal than dying. Getting born is much trickier. Over the 200,000 years of mankind’s history, it is estimated that 109 billion individuals died, compared to 8 billion now alive. Thus, about 7% of the people who ever lived are now alive. But they will die too: c’est la vie.
The chart below suggests that human population was stable until about 2000 BCE. From 2000 BCE, population grew slowly until around the 17th century, with some catastrophes along the way like the Black Death of the 14th century, which probably killed one-third of Europeans. Then, unexpectedly, the population exploded from the 18th and 19th centuries on (you can play with the graph on the website of Our World in Data). In 1820, life expectancy at birth was 36 years in Western Europe and Japan; its average was still only 24 in the rest of the world, the same level where it had been everywhere on Earth around the year 1000. In the United Kingdom, it was 40 years in 1820, and had grown to 77 in 1999.
The Industrial Revolution, which greatly increased incomes (GDP per capita), played a role in supporting and fuelling the population explosion. As Angus Madison noted, “there has been significant congruence over time and between regions, in the patterns of improvement in per capita income and life expectation [expectancy].” (See Angus Maddison, The World Economy, Organization for Economic Co-operation and Development, 2003, 2006.)
We met Angus Maddison before when we looked at his estimates of GDP per capita since year 1 and the astonishing boost in its trend at the time of the Industrial Revolution. Increasing GDP per capita requires that total output (GDP) increase more than population. This growth phenomenon, which had never happened until it started in the Netherlands and the UK, requires institutions that don’t obstruct free markets and entrepreneurship. In the late 18th and early 19th century, ordinary people’s constant fear of starvation was abolished in countries that got on the bandwagon of the Industrial Revolution. Many countries that had feeble industrial revolutions were able to partly benefit from others’ through trade.
Note that the Industrial Revolution was not only a matter of factories, even if mass production of common consumption goods for ordinary people, like clothes and everyday objects and tools, was an important step and a major achievement. But it was preceded and accompanied by a financial revolution, not to mention the preceding centuries of commerce (even if often restrained by political rulers). Without this institutional background, widespread technological progress cannot occur. A whole industrial civilization was born and led to large progress in agriculture and intangible services too. Today, in America, two-thirds of consumer expenditures go to services—such as education, health, housing, home deliveries, and such—instead of food and hard stuff. Consumers now want mainly services because food and manufactured gadgets cost so little.
As my post “The Significance of Botched Industrial Revolutions” also indicated, some industrial revolutions started but failed, and some countries never had anything close. For us in Western countries (plus a few Asian countries), the future depends on our capacity to reinforce the institutions that allowed the Industrial Revolution to happen. Ortega y Gasset warned us that civilization—industrial civilization—is not guaranteed against political folly.
Another lesson relates to the environmental scares of the 1960s and 1970s in the form of “the population bomb,” title of a book by Stanford University biologist Paul Ehrlich. Environmentaliats advocated massive state dirigisme to control population and save mankind. In 1965, the New Republic announced that the “world population has passed food supply,” that “the famine had started,” and that world hunger would be “the single most important fact in the final third of the 20th century.” In reality, the final third of the 20th century brought a historical decrease of poverty in the world. The “freedom to breed is intolerable,” ecologist and microbiologist Garrett Hardin pontificated. Economist Julian Simon argued against Ehrlich that man was “the ultimate resource,” title of his 1981 book: more individuals on our planet are not a problem but, on the contrary, bring more contributors in the solution of mankind’s problems—besides each individual being a life worth living. Simon made and won a famous bet with Ehrlich about the exhaustion of resources. The story is told in Paul Sabin’s The Bet: Paul Ehrlich, Julian Simon, and Our Gamble over Earth’s Future (2013); if you don’t have time to read the whole book, you may like my short review on Law and Liberty.
We may rephrase the issue in terms of so-called “carrying capacity.” National Geographic defines it as
a species’ average population size in a particular habitat. The species population size is limited by environmental factors like adequate food, shelter, water, and mates. If these needs are not met, the population will decrease until the resource rebounds.
Applied to the Homo Sapiens, this Malthusian approach neglects the crucial fact that human individuals want more than “adequate food, shelter, water, and mates,” and are indeed capable, with the right institutions, to obtain much more. The Encyclopedia Britannica adds “social requirements” to the conditions of carrying capacity, although the term “requirements” seems to limit the scope of voluntary social cooperation:
carrying capacity, the average population density or population size of a species below which its numbers tend to increase and above which its numbers tend to decrease because of shortages of resources. The carrying capacity is different for each species in a habitat because of that species’ particular food, shelter, and social requirements.
Economics helps us understand how currently living humans have come to constitute 7% of all those who lived in 200,000 years. It also enables us to look at the environmentalists’ scares and other social matters with a cool head.
