Global population to peak in 2070
11:05 02 August 01
The world's population may reach a peak of nine billion as early as 2070 and then start to shrink, according to a new analysis by Austrian
Wolfgang Lutz, of the International Institute for Applied Systems Analysis, and his team created thousands of simulations of the future world
population and evaluated them, assigning probabilities to each range of possibilities.
They think there is an 85 per cent chance that the global population will stop growing before the end of the century - most probably by 2070. More
than one third of people alive in 2100 will be over 60, they say. In Japan, the figure will be one half.
Detailed population projections are vital for governments planning long-term economic strategies, says Lutz. However, Nico Keilman, an economist at
the University of Oslo, warns that population projections are notoriously unreliable. The "probabalistic statements are themselves uncertain to some
extent", he writes in the journal Nature.
Declining fertility rates
Lutz thinks declining fertility rates around the world are the main driving
force behind the slowing in population growth.
"We hope these findings will help people get away from the apocalyptic view that the population will explode in the future," he told New Scientist.
"Humankind can control the future by controlling fertility."
The population will start to shrink when the average number of children per woman falls below 2.1 (this figure is above two to provide for childhood
mortality). "We are assuming that fertility levels in most parts of the world will soon go below the replacement level," Lutz says. "In some
countries, like India, it will probably go down to 2.1 and then stay constant."
In some parts of Europe, fertility levels have already dropped dramatically. In Spain, the average number of children per woman is 1.2. In Russia the
figure is 1.1.
"In Eastern Europe and the former Soviet Union, we have already seen the peak of population size, and it will decline in the future," Lutz says.
"However, the US will continue to grow due to immigration." He adds: "This shows the notion that poor countries are growing and rich countries are
shrinking is not true."
Lutz thinks fertility is dropping as more women are able to go for "quality" of children, rather than quantity. "The reason it's dropping below
the replacement level in Europe is probably because of fundamental changes to the role of women in society," he adds.
But mortality from AIDS and other poverty-related illnesses is also a key factor, says Lutz. The possibility of future unpredicted health disasters -
such as another AIDS - is also included in the team's projections.
Several groups are working on population predictions. In September, the
United Nations Population Fund will release a new report projecting that the world population will peak at 9.3 billion by 2050.
Lutz says there are several key differences in the way the UNPF has made its predictions, compared with his team's approach.
"The UN does not consider climate change - which we think will hit agricultural production in Africa and southern Asia in particular," says Lutz.
"We are also a lot more pessimistic about African mortality than the UN. In 2020, we assume life expectancy in Africa to be about 10 years lower than
While more developed countries will see a "window of opportunity" when a relatively large (though ageing) workforce is available, Africa and
southern Asia will continue to struggle, say the team. "I'm not optimistic about that part of the world at all," Lutz says.