World population passes eight billion milestone

Some time today Earth’s population is expected to pass eight billion, according to the United Nations.

Population density can be seen in the crowded streets of Hong Kong. Picture: Getty Images

Some time today Earth’s population is expected to pass eight billion, according to the United Nations, which will announce the milestone in events staged in New York and at the COP27 climate conference in Egypt.

The figure, according to projections by the UN Population Fund, has come thanks to longer lifespans and the rapid growth of some nations in Asia and sub-Saharan Africa.

It came only 11 years after the figure hit seven billion, but amid projections that this “unprecedented growth” was now slowing. There will not be nine billion people until 2037, according to the UN.

Its officials sought to cast it as a cause for celebration while at the same time issuing warnings of the challenges that lie ahead as humanity reaches a predicted peak population of about 10.4 billion sometime in the 2080s.

“It’s a reflection of our success as a species, to be able to proliferate the way we have,” John Wilmoth, director of the population division in the UN department of economic and social affairs, said. “At the same time it raises questions about our impact on the world.”

Although the population has grown most rapidly in the modern era, more than trebling in the 20th century, average fertility rates have been dropping since 1950. Then the average woman had five children; by last year it was 2.3 and by 2050 it is expected to drop to 2.1.

However, fertility rates remain far higher in some of the least developed nations. The UN projects that eight countries – the Democratic Republic of Congo, Egypt, Ethiopia, India, Nigeria, Pakistan, The Philippines and Tanzania – will account for more than half the population increase by 2050.

India is now drawing level with China, with a population of 1.4 billion, and is expected to surpass it next year. China’s population may begin to shrink next year, according to the UN. The fertility rate there was 1.16 last year.

“Many of us get married very late and it’s hard to get pregnant,” Tang Huajun, 39, a father of one from Beijing, told Reuters news agency.

China’s one-child policy, imposed from 1980, was dropped in 2015. Beijing began allowing couples to have up to three children last year in an effort to raise a birthrate that had slipped to 1.16 to an “appropriate” level.

For developing nations with booming populations, there are concerns that rapid growth will make it more difficult to improve education and to hit goals for sustainable development, as part of efforts to reduce climate change.

But population growth has had less of an impact on climate change than the growth in “the scale of our activities”, Professor Wilmoth said. “There has been an increase in the size of the impact that each person is having on the environment,” he added. “That per capita impact has changed more than the number of people.”

The threat to the environment “won’t go away even if we had a smaller population”, he said, although he added: “Having a somewhat larger population of course increases the impact.”

Besides the growth of some nations, improvements in public health have led to longer lifespans. Women, on average, are doing better on that score than men. Women born in 2019 had an average life expectancy of 73.8 years, whereas for men it was 68.4 years.

This advantage was observed around the world: in Latin America and the Caribbean the difference was seven years, in Australia and New Zealand it was 2.9 years.

“There has always been an advantage for women in terms of the disease of old age,” Professor Wilmoth said, although in the past this was balanced by the number of women who died in childbirth. Women “have a really big advantage in cardiovascular diseases,” he said. “In this period of human history, cardiovascular diseases are the major killer.”

In her book 8 Billion And Counting, Jennifer Sciubba says in the year AD1 there were 300 million people, women gave birth to at least four children on average but many starved before the end of their child-bearing years and life expectancy at birth was 10. “Those alive in 1750 were less than 1 per cent of humans ever born,” she writes. “The almost eight billion of us alive today [the book was published in March] represent about 7 per cent of the 108 billion who have ever taken a breath.”

By 1804 the population reached a billion, but it really took off during the 20th century: from 1.6 billion to five billion by 1987, and six billion by 1998. In that year Christian Mortensen died at the age of 115, the oldest man whose age had been verified by researchers.

Professor Wilmoth, now of the UN but then a professor of demography at the University of California, was the author of a paper establishing this. He also became a friend of Mortensen, telling him that given his predilection for smoking Danish cigars, his long life was partly a matter of luck.

But the cohort of people living past 100 was growing rapidly, Professor Wilmoth said. “In countries like the US and the UK, it’s doubling roughly every 10 years.”

He said the eight billion count was an estimate. “For some countries we have very complete censuses. For some countries we haven’t had a census for 30 years or more. So it’s [based on] counting the population in some cases and modelling it in others.”

Antonio Guterres, the UN secretary-general, said the world should celebrate the milestone, “while considering humanity’s shared responsibility for the planet”.

The Times