Fred Pearce, New Scientist 27 Sep 09;
THERE is a pervading myth that efforts to fight climate change and other environmental perils will be to no avail unless we "do something" about population growth. Even seasoned analysts talk about the threat of "exponential" population growth. But there is no exponential growth. In most of the world fertility rates are falling fast, and the countries where population growth continues are those that contribute least to our planetary predicament.
Back in the late 1960s, when Paul Ehrlich wrote his seminal book The Population Bomb, rapid population growth was arguably the number 1 threat to the planet's future. Many believed that only strict birth control could prevent doomsday. But after scandals about forced vasectomies in India and China's draconian one-child policy, such views fell into disrepute. What's more, Ehrlich's prediction of hundreds of millions of deaths from famine in the 1980s fortunately failed to be borne out.
Now the demographic monster has become a hot topic again. Yet the arguments still don't fit the reality. The population "bomb" is fast being defused. Women across the poor world are having dramatically fewer babies than their mothers did - mostly out of choice, not compulsion. Half a century ago, the worldwide average for the number of children a woman had was between five and six. Now she has 2.6. In the face of such a fall it is hard to see what more "doing something" about global population might achieve.
Half the world now has a fertility rate below the replacement level, which, allowing for girls who don't make it to adulthood, is around 2.3. This includes most of Europe, east Asia, North America and the Caribbean. There are holdouts in a few Muslim countries - but not Iran, where fertility is 1.7 - and many parts of Africa. But rich or poor, socialist or capitalist, Muslim or Catholic, secular or devout, with tough government birth control policies or none, most countries tell the same story.
This hasn't yet stopped the world's population from rising. It stands at 6.8 billion, and is growing by 75 million a year. This is mostly because the huge numbers of young women born during the 20th-century's worldwide baby boom are still fertile: they may typically only have two children each, but that is still a lot of babies. Soon, however, if fertility rates continue to decline, each generation of women will be smaller than the last.
Of course fertility rates may not continue to decline, but to date the evidence of countries that have got down to the replacement level is that they don't stick there, they carry on declining. The reasons for this may have a lot to do with the changing position of women in society. Where men take a greater role in bringing up children, and the state intervenes to help working mothers, fertility rates stay quite close to replacement. Where they do not, then super-low fertility may follow; women, in effect, go on childbirth strike.
Even if the world population does stabilise soon and starts to glide downwards, that won't solve the world's environmental problems. The real issue is not overpopulation but overconsumption - mostly in rich countries that have long since given up adding substantial numbers to their population.
Take one measure: carbon dioxide emissions. Stephen Pacala, director of the Princeton Environmental Institute, calculates that the world's richest half billion people - that's about 7 per cent of the global population - are responsible for 50 per cent of the world's emissions. Meanwhile, the poorest 50 per cent are responsible for just 7 per cent of emissions. One American or European is more often than not responsible for more emissions than an entire village of Africans.
Every time those of us in the rich world talk about too many babies in Africa or India, we are denying our own culpability. It is the world's consumption patterns we need to fix, not its reproductive habits.
Fred Pearce's book Peoplequake will be published in February 2010 by Eden Project Books
