In the early 21st century population features on the political agenda in the developed world only as a source of concern about pensions, ageing, “low” birth rates and demographic “decline.” These worries are largely misplaced. The far more serious issue of human population growth has fallen off that agenda. Yet world population is set to rise 40 per cent from 6.5 billion to 9.1 billion by 2050 while UK population is projected by the Government to increase by a sixth, or 10.5 million people, to 70.7 million by 2074.

These numbers carry huge environmental implications. Many people now argue that numbers do not matter because environmental problems can be solved by modifying lifestyles and technologies. Yet increased eco-efficiency is routinely drowned out by increases in volume. Population growth since 1990, and related emissions, accounts for much of the UK’s projected failure to meet its 2010 CO2 emissions target, for example. People also have certain irreducible needs – for food, water, housing – and in an increasingly wealthy world these look certain to grow and further “needs” to arise. .

In the UK strains are obvious over housing, water, energy, traffic, land-use, noise. Congestion is widespread, “tranquillity” (as defined by the Campaign to Protect Rural England) is disappearing and the effects on mental health, while unmeasurable, are probably serious – depression and stress are widespread and various forms of “rage” have grown in recent years. England is by some measures the world’s fourth most crowded country; seven out of 10 Britons think the UK is overcrowded. Emigration is at record levels, with lack of space and quality of life the main causes. OPT calculates that the UK will require over seven million more houses by 2074 – more than twice the number of houses in London – while the Office of National Statistics ascribes 59 per cent of new housing need to population increase ( the remainder is ageing and smaller households.

As important, the UK is “freeloading” on the rest of the world – notably poorer countries. Ecological footprint studies show that the UK requires 3.6 “UKs” to feed and supply itself - the “other” 2.6 UKs (the extra land required for our lifestyles) are abroad. In a world of depleting resources, this is a dangerous strategy. Each increase in the UK population makes this freeloading worse. The UK, in other words, has a serious overpopulation problem but it is “hidden” by virtue of its privileged – and arguably exploitative - position in the global economy. The same applies to other developed (i.e. high-impact) countries suffering population “decline.”

Population is not being addressed because it is seen as too sensitive. There is also a feeling that “nothing can be done” about population growth. This is one reason why 150 million couples worldwide have no access to contraception, 350 million have only limited access – and why it’s estimated that over 200,000 women die every year from pregnancies they did not want. Yet the trade-offs between population and resources are seen clearly in developing countries, which is why 66 per cent of African countries have population policies compared with 25 per cent in 1976. The irony is that the UK, which is more crowded and does more per capita global environmental damage than virtually all of those countries (for example, one Briton produces as much CO2 as 260 inhabitants of Chad), does not have a population policy.

A further reason why population is neglected is immigration, which in the UK accounts for 83-84 per cent of the projected rise in numbers (ONS). Many people are reluctant to raise this issue for fear of being labelled racist. Immigration is said to be important for the UK’s economy but the evidence suggests that it is creating a low-wage economy with serious effects on employment and living standards among working-class communities and that its only contribution to “growth” is through the addition of more people. By increasing the number of high-impact consumers, it also adds to the UK’s burden on the rest of the world. A review by Robert Rowthorn and David Coleman, respectively professors of economics at Cambridge University and demography at Oxford University, concluded that the “economic consequences of large-scale immigration are mostly trivial, negative, or transient; that the interests of more vulnerable sections of the domestic population may well be damaged; and that any small fiscal or other economic benefits are unlikely to bear comparison with immigration’s substantial and permanent demographic and environmental impact.”

Immigration and higher birth rates are said to be needed to prevent ageing “problems.” Yet serious analyses of this issue (the Pensions Commission, the Tomorrow’s Company report) do not support this argument, for the simple reason that new workers eventually become pensioners. To maintain a given support ratio (worker to non-worker), population growth would thus have to be maintained literally indefinitely - clearly unfeasible. But if existing populations in the developed world are too high, as the OPT argues, large-scale additions to the population merely add to global environmental damage. The sensible solution is not “panic natalism”, and endlessly rising numbers, but gradually to remodel the retirement and savings system to reflect the (welcome) reality of people living longer.

Another reason for neglect of population is the poor human rights record of “coercive” population policies in India and China. In OPT’s view, these reinforce the need for non-coercive population policies now, and not just in developing countries. China is in one sense a vision of the future - but a nightmare future in which collapsing life-support systems mean that coercive population policies are the only alternative to conflict and die-off (the one-child policy is officially estimated to have prevented some 400 million births – the effect being that its population is currently 1.3 billion instead of 1.7 billion). Most current estimates of a sustainable world population are around the 2 billion figure; however, James Lovelock, the scientist and author of the Gaia hypothesis, believes the figure is currently 1 billion but will reduce to half a billion as shortages and conflicts take their toll.

Climate change is seen as the biggest threat to the planet in the 21st century. Yet population growth is a key factor in climate change as it is in virtually all the other ingredients of environmental crisis. To stabilise the climate, the world needs to reduce its annual CO2 emissions to about nine billion tonnes - 60 per cent below the 1990 level of 22 billion tonnes (Intergovernmental Panel on Climate Change). With world population at 9.1 billion in 2050, this equates to one tonne of CO2 per person – roughly a tenth of current UK per capita emissions. An equitable sharing out of CO2 emissions among the world’s nations as envisaged by “contraction and convergence”-type models suggests we will thus need to reduce UK emissions by about 90 per cent. For comparison, the UK managed to reduce its emissions by only 5.5 per cent below 1990 levels during the period 1990-2005, despite highly favourable conditions such as the shift from coal to natural gas for electricity generation.

OPT believes that technology and lifestyle changes by themselves will simply be incapable of delivering cuts of this magnitude or anything near it and that population levels must play a part in the solution. Population policies built on education, awareness and family planning have already succeeded in many countries. A voluntary “two-child” policy in Iran, for example, halved the family size in just eight years, from 5.2 children in 1988 to 2.6 in 1996. OPT believes similar policies are needed in the UK in the context of an overall “target” sustainable population figure. Footprinting research suggests this would be at most 20-30 million. Reducing the UK’s global impact by reducing its population is probably the biggest service we could render to the planet.

This briefing written by David Nicholson-Lord and published July 2006.