UNDER THE MICROSCOPEThe 44 most developed countries in the world now have the lowest fertility rates, writes Dr Willam Reville
THE POPULATION of the world quadrupled over the 20th century and stands today at 6.7 billion. The UN projects that world population will peak around nine billion by 2050, and will then slowly decline. Such numbers press too heavily upon the Earth's carrying capacity, although developments in agriculture have greatly expanded this capacity beyond past estimates of its size.
The current population situation is exacerbated by the fact that numbers are increasing most rapidly in the poorest and least developed parts of the world, causing acute problems in many regions. Stabilisation, followed by decline of population numbers in the developing world would greatly ease this hardship.
Some people also advocate a reduction in birth rates in the developed world, which seems very ill-advised to me since birth rates there are already dangerously below replacement rates.
World population growth rate peaked in 1970 and is now in decline. Previous estimates of population growth - global population of 15 billion in 2050 - have been seriously revised downwards. Some readers will remember the best-selling 1968 book, The Population Bomb by Paul Ehrlich, in which he predicted that hundreds of millions would die of famine in the 1980s. He later revised this figure upwards to some billions! I don't recall him achieving any publicity for an admission that he got things so spectacularly wrong.
A birth rate of an average of 2.1 children per woman (replacement level) is necessary to keep population numbers constant. In 2005, the average woman in the developing world bore 2.9 children, down from an average approaching six babies per woman in the 1970s. By 2005, birth rates in 20 developing countries had fallen below replacement levels and the UN predicts that by 2050, 75 per cent of developing countries will have below-replacement fertility. Nevertheless, the population of the world's 50 least developed countries is projected to more than double from 0.8 billion in 2005 to 1.7 billion in 2050. In some countries (Afghanistan, Burundi, Chad, Congo, East Timor, Liberia, Mali, Niger, Uganda), population will at least triple. In the remainder of the developing world, growth will be less rapid but still robust, rising from 4.5 billion in 2005 to 6.1 billion in 2050.
The 44 most developed countries in the world, which contain 19 per cent of its population, now have the lowest fertility rates. Almost all have fertility rates below replacement level and 15 of them, mostly in southern and eastern Europe, have fertility rates below 1.3 children per woman - unprecedented in human history. For example, Japan, Italy, Spain, Germany and most of the states descended from the USSR will have significantly smaller populations in 2050 than they have now. The US is an exception, with a fertility rate of 2.1. Because of low fertility rates, the population of the developed world will remain static between 2005 and 2050 at about 1.2 billion.
When fertility rates decline to below 1.3 the population shrinks greatly over a few generations and, of course, will decline to disastrous levels if the fertility remains at this low level. The German and Italian governments are worried about this and now offer inducements to women to bear more children.
The UK Optimum Population Trust (OPT) advocates achieving optimum population size for sustainable living. It calculates that a child born in the UK carries a carbon footprint 100 times the footprint of a child born in Ethiopia (secular original sin!). OPT outlined its position in an editorial on July 24th last in the British Medical Journal. It argues for a decrease in birth rates not only in the developing world, but also in the developed world and advocates that UK couples should target two children per family as an upper limit. Of course, many people who are persuaded by the general argument will limit children to one, or none. Since the UK fertility rate currently stands at 1.85, any further reduction would seriously reduce population numbers. Also, when fertility rates fall below replacement rates the ratio of working age people to retired people falls rapidly and pretty soon there are too few workers to do essential work and to pay the taxes that sustain a welfare state.
UK fertility rates are rising slowly, largely because of higher birth rates among immigrants. The OPT arguments will have least affect on immigrants and greatest affect on indigenous UK stock, so the overall effect, if this advice were generally adopted, would be to quickly change these relative proportions in the general public. This would exacerbate already serious inter-racial/inter-cultural tensions.
In my opinion the OPT advice, if applied to the developed world, would introduce more serious problems than the problems it might eliminate. The solution to high carbon emissions in the developed world is to drastically reduce them, not to stop breeding and risk the disappearance of the race.
• William Reville is associate professor of biochemistry and public awareness of science officer at UCC -http:// understandingscience.ucc.ie