World population growth peaked in 1968 and has roughly halved since
Humanity grew by 2.1 percent a year in 1968, the very year Paul Ehrlich published The Population Bomb. The annual rate has since fallen to about 1.1 percent, and forecasters keep trimming their estimates of when the total will stop rising and begin to shrink.
The long view explains the alarm. Farming, which spread after the ice retreated around 10,000 BCE, allowed populations to swell in Europe, the Americas and China. Numbers have climbed without pause since the Black Death ended around 1350. The world reached roughly 1 billion by 1804, about 1.6 billion around 1900 and 2.3 billion by 1940. The quickest doubling, from 2.5 to 5 billion, took just 37 years between 1950 and 1986, driven by medicine and higher crop yields, with the Haber process for fertiliser playing a large part. Today there are about 8 billion of us.
Worry about numbers outrunning food dates to Thomas Malthus, whose imagined catastrophe has population exceeding farm output and triggering famine, war and collapse. Ehrlich revived the fear in 1968, arguing that overpopulation is really about overconsumption and a population's inability to live without draining non-renewable resources. Modern proponents link population, growth and consumption as main drivers of climate change, and the IPCC's 2022 assessment named GDP per capita and population growth as the strongest drivers of carbon dioxide emissions.
Critics answer that growth is already slowing and the total will likely peak this century. Many demographers dispute the premise that Earth cannot support the projected numbers, noting that technology and falling birth rates change the maths. Economists and historians point out that sustained famines have usually followed war, price controls and repressive regimes rather than sheer headcount. Others say the debate distracts from poverty or overconsumption, carries racist undertones, or unfairly targets the Global South, where most growth occurs.
The forecasts keep moving. A 2020-era UN estimate had the world levelling out near 10.9 billion around 2100. The UN's 2024 report instead expected a peak of 10.29 billion in 2084, easing to 10.18 billion by 2100, about 6 percent below its 2014 estimate. Some researchers using national birth registries from 2022 and 2023, covering half the world, argue that fertility may already have dropped below replacement for the first time ever, with a peak of roughly 9.5 billion around 2061.
Source: Human overpopulation
