Earth Heading for 5 Billion Overpopulation?

March 25, 2009 • Daily Email Recap

Thanks to Eric Rimmer for this notice from OPT.



March 16 2009 – For immediate release


Conference to discuss sustainable population levels

A conference next week will attempt to answer a question that has fascinated scientists for at least three centuries but has now taken on a new urgency – how many human beings can the Earth support?

With the earth’s population growing by 78 million – a new Germany – each year, the Optimum Population Trust has assembled a distinguished group of experts to discuss the scientific case for lowering global and national populations to environmentally sustainable levels.

Speakers include: Tim Dyson, professor of demography at the London School of Economics; Prof. Andrew Watkinson, former director of the Tyndall Centre for Climate Change Research; Robin Maynard, campaigns director of the Soil Association; John Guillebaud, emeritus professor of family planning and reproductive health at University College, London; Prof. Chris Rapley, director of the Science Museum; Jonathon Porritt, chair of the Sustainable Development Commission; and Sara Parkin, founder-director of Forum for the Future and former co-chair of the Green Party.

Climate change, growing food shortages, the projected peaking of oil and gas supplies and the growth of international migration have focused renewed attention on population growth, with senior figures from both Labour and Conservative parties speaking recently of the need for population policies and leading figures in the green movement, including James Lovelock, author of the Gaia theory, warning of the dangers of overpopulation.

Lovelock agrees with many other commentators that the environmental crises facing humanity in the 21st century will significantly reduce the earth’s carrying capacity. He has said this could shrink the world’s sustainable population to 500 million – 1 billion, compared with a current total of 6.8 billion.

The Dutch inventor of the microscope, Antoni van Leeuwenhoek, is thought to have been the first to estimate the maximum number of people the earth could support: in 1679 he put it at 13.4 billion. Since 1950 there been many estimates of global carrying capacity, ranging from 0.5 billion to 1,000 billion. Based on ecological footprint and biological capacity data which have become available over the last decade, OPT estimates the world’s sustainable population currently at five billion and the UK’s at 18 million (actual figure, 61 million).

However, these figures are predicated on current levels and patterns of consumption. Greener lifestyles in the UK could push up its sustainable population; by contrast, if the world as a whole grows richer and consumes more, this will reduce the planet’s carrying capacity. If present trends continue, by 2050, when the UN projects world population will be 9.1 billion, there will be an estimated five billion more people than the Earth can support.

The subject of global and national carrying capacity generated much interest among ecologists and biologists in the 1960s and 1970s but until recently was out of favour, along with the population issue as a whole. In 1969, for example, the Royal Geographical Society held a symposium on The Optimum Population for Britain with an audience of mainly professional biologists. With the UK’s population then standing at 54 million, 90 per cent of participants thought the optimum population for Britain had already been exceeded.

David Nicholson-Lord, OPT policy director, said: “With global and UK population rising so fast, there is an urgent need to bring the issue of sustainable populations to the top of the political agenda. The Conservative leader, David Cameron, has said we need a ‘coherent strategy’ to address population growth and last autumn the immigration mister, Phil Woolas, said the UK needed a population policy. It’s high time the parties turned these words into action.

“We also hope the conference will help dispel the myth that big is good in relation to population and that population decline is a sign of national failure. In terms of quality of life and sustainability, the most ‘successful’ nations are generally the smallest. And what is arguably Britain’s most creative period – the era that produced Shakespeare – came at a time when her population was probably five million at most, a twelfth of today’s numbers. In population terms, small is not only beautiful: it works well too.”

The conference, Environmentally Sustainable Populations: The scientific case for population policy – and ways of achieving sustainability, will be held at the Royal Statistical Society on March 26.


See, contact Julie Lewis, administrator, Optimum Population Trust, or telephone 07976 370221

NOTES FOR EDITORS: The OPT, a think-tank and campaign group, was founded in 1991 by the late David Willey. Its main aims are to promote and co-ordinate research into criteria that will allow the sustainable or optimum population of a region to be determined. Its patrons include Sir Partha Dasgupta, Frank Ramsey professor of economics at Cambridge University; Paul Ehrlich, professor of population studies, Stanford University; Jane Goodall, founder, the Jane Goodall Institute, UN Messenger of Peace; John Guillebaud, emeritus professor of family planning and reproductive health, University College, London; Susan Hampshire, actor; Aubrey Manning, broadcaster and professor of natural history, Edinburgh University; Professor Norman Myers, visiting fellow, Green College, Oxford; Sara Parkin, founder director and trustee, Forum for the Future; Sir Jonathon Porritt, chairman of the UK Sustainable Development Commission; and Sir Crispin Tickell, director of the Policy Foresight Programme, James Martin Institute for Science and Civilisation, Oxford University.

Current World Population


Net Growth During Your Visit