The UN Population Fund report predicts that the global population could reach 10.5 billion by 2050, up from 6.8 billion today, unless urgent action is taken to reduce fertility rates.
It says that even its medium-growth forecast of 2.3 billion more people by 2050, which assumes a fall in average fertility from 2.56 to 2.02 children per woman, would make it much harder to achieve the cuts in carbon emissions needed to prevent catastrophic climate change.
The report says that reducing population growth would allow the 2050 target for global average emissions per person to be increased significantly above the 2 tonnes recommended by Lord Stern, the author of an influential government report on global warming in 2006. Living standards would be higher because each person would be able to emit more CO2.
The report says: “No human is genuinely carbon neutral. Therefore, everyone is part of the problem, so everyone must be part of the solution in some way.
“Each birth results not only in the emissions attributable to that person in his or her lifetime, but also the emissions of all his or her descendents.”
The report rejects the idea of Chinese-style laws to control population but says that a similar outcome could be achieved by promoting contraception and ensuring that women are better educated.
It says that 215 million women, mainly in developing countries, want contraception but have no access to it. Funding from donor countries for the UN’s birth control programme has fallen from $723 million (£431 million) at its peak in 1995 to $338 million in 2007.
The report also says that the longer women remain in education, the fewer babies they have. Women who have never gone to school have an average of 4.5 children. Those who complete one or two years of university have 1.7.
“Dollar for dollar, investments in voluntary family planning and girls’ education would, in the long run, reduce greenhouse gas emissions at least as much as investments in nuclear or wind energy,” the report says.
It reveals that, contrary to received wisdom, rates of unintended pregnancies are higher in rich countries than in poor ones. In Europe, the US, Australia, Canada, Japan and New Zealand, an average of 41 per cent of pregnancies are unintended, compared with 35 per cent in developing countries.
However, most of the projected increase in population will be in developing countries. The population of Africa is expected to double to 2 billion by 2050. The population of all developed countries is likely to rise only 3 per cent, though this masks big differences, with the US population expected to rise by a third to 400 million and Japan’s expected to decline by a fifth to 100 million.
The Population Fund acknowledges that reducing population growth in developing countries would have little immediate impact on emissions because their inhabitants have relatively small carbon footprints. But it says that the savings would increase as the economies of developing countries grew and levels of consumption — and, therefore, emissions — rose.
The report says that population growth is only beginning to be recognised as an important topic in international negotiations on climate change. It will not be discussed at next month’s UN summit in Copenhagen.
“Fear of appearing supportive of population control has, until recently, held back any mention of ‘population’ in the climate debate.”
A spokeswoman for CAFOD, the Catholic aid agency, said that it did not support the promotion of birth control in poor countries, where the “underlying causes of large families . . . are lack of education of women and unequal power relationships between men and women”.
