Sustainable development became a fashionable phrase in the 1980s, but its meaning was always somewhat uncertain. “Treating the Earth as if we intended to stay” – words used once on the BBC – covered the sustainable aspect. But development? Here we get into other arguments. For many development meant following the model of industrial countries regardless of the geographical circumstances of others with different cultures and economic resources.

Hence the somewhat artificial classification of so-called developed, developing, under-developed and even over-developed countries, which has so long distorted the international debate on trade, economics and diplomacy. In my view current thinking about for example “growth” needs to be replaced by new ways of measuring health, wealth and happiness, with proper respect for the limited natural capital of the Earth.

Population growth: fundamentally unsustainable?

How then does population come in? It is a long story. It was Thomas Malthus who in 1798 wrote “Population, when unchecked, increases in a geometrical ratio [1-2-4-8 etc]. Subsistence only increases in an arithmetical ratio [1-2-3-4 etc.]”, and referred to “the perpetual struggle for room and food”. This judgment greatly influenced Charles Darwin in working out the mechanisms of evolution by natural selection. It has constantly been challenged, notably in the 1970s, when many believed that technology would or could solve all problems. Neo-Malthusianism was regarded as sinful, while others referred to “Malthus postponed”.

1800-2000: Humans faster than rabbits?

The rise in human population over the last 10,000 years has been amazing by any reckoning. No one was there to count, but with agriculture and the growth of towns and cities population rose from around 6 million 10,000 years ago to around 1 billion in 1800. Thereafter it rose from around 2 billion in 1930 to 4 billion in 1975 and to 7 billion in October 2011, with the prospect of reaching somewhere near 9 billion by the middle of this century.

What has been called the Medean hypothesis suggests that living organisms, whether bivalves, swallows, beetles or humans, can multiply until they reach environmental and other boundaries, and will then diminish or destroy themselves. This has happened many times in biological history and even in the history of societies, and is a well recognized part of the process of evolution.

It even has an equation to describe it: I=P*A*T in which I (population size) equals P (affluence per capita), A (consumption and production), and T (the level of environmentally damaging technology).

Global sWarming: humans take on geological time

Population issues are of course linked with everything else, and cannot be understood without reference to the widespread impact of multiplying humans (10,000 more every hour and almost 80 million more a year) on the surface of the Earth. No wonder it has been called global swarming.

The impact has been so great that many geologists would like to see it recognized as a new geological epoch – the Anthropocene – to succeed the Holocene which began after the last spasm of the ice ages some 10,000 years ago. On this reckoning the Anthropocene began some 250 years ago with the industrial revolution. It has to be understood in terms of human-made changes in the land, sea and air of the planet, and at present its effects are increasing every day: for example in reduction of forest cover, acidification of the oceans, and destabilization with warming of the climate.

Anthropocene: development, damage and denial

Humans light up the world: the earth at night.
Data courtesy Marc Imhoff of NASA GSFC and Christopher Elvidge of NOAA NGDC. Image by Craig Mayhew and Robert Simmon, NASA GSFC.

The problems of the Anthropocene have been increasingly recognized, notably perhaps with the publication of Rachel Carson’s book Silent Spring in 1968. Since then there has been a series of international conferences, beginning at Stockholm in 1972. But the population aspects, in particular measures to cope with the problem, have been curiously neglected. There was a somewhat inconclusive United Nations conference on population in Cairo in 1994, but the issues touched on difficult political and especially religious susceptibilities, in particular over contraception and the role of women, which made many prefer to look the other way.

Any room for optimism?

All that is now changing. There has been much academic work not only to improve understanding of what is happening but also to work out what could and should be done. In the richer parts of the world, fertility rates are already falling. On the basis that average replacement rate is 2.1 children per woman, many now have much fewer, for example in Russia, Germany and Italy (in spite of the Pope). What has been called the demographic transition is visible almost everywhere as living standards rise, education is improved, the status of women is increased, and more children survive childhood (thereby reducing the pressure for more children).

This is not to say that problems of excessive human numbers are solved. With increasing damage to the environment, arising among other things from pollution, climate change, and pressure on resources (what has been labelled Bankrupting Nature in a recent book), together with attachment to defective economic theory and modelling (providing what might called the consumptive rather than the consumption society), the prospects can be seen as bleak. To manage otherwise requires us to think differently across the spectrum. Little is more difficult.


November 2012

population 3895997146_6a71f0b037_o.jpg

Two members of the Africa Muslim Agency attempt to brace the front gate as thousands of mothers carrying their malnourished children try to push into the therapeutic feeding center.
Fernando Henrique

About the author


Sir Crispin Tickell has long been a pioneer in linking environmental and in particular climate change to the worlds of politics and... (Read more)