COMMENTARY: Overpopulation is too big a problem to ignore

Posted: 26 October 2011

Author: Sir John Sulston

Sir John Sulston, Nobel prize-winning biologist and chair of the Royal Society’s ongoing study into People and the Planet, warns here that population must not be ignored if we are avoid a ‘vast human tragedy'. 

Population is an uncomfortable subject for politicians; the idea of influencing family size has unpleasant associations with state coercion. But population does need to be talked about. Rising numbers and the associated consumption of resources is putting an unsustainable load on Earth. That is why the Royal Society, the national academy of science, has begun a comprehensive study, which I am chairing.

Since 1950, the global population has swelled almost threefold. The current population of almost seven billion is forecast to rise to more than nine billion by 2050. This is increasing demands on the finite resources of our planet, reducing our ability to bring people out of poverty and causing climate-warming increases in carbon dioxide in the atmosphere, a decline in biodiversity and conflict for resources.

There should be a deafening chorus calling for global debate and action, but there isn't. Part of the problem is its complexity; it's not simply a case of "more people". While in some countries fertility remains high, in others it is very low. For example, because of plummeting birth rates, increasing life expectancy and little immigration, Japan's greying population is set to shrink. The same is true in Western Europe.

Some argue that as fertility rates globally are in general decline, we do not need to do anything. However, population projections are based on expectations of human behaviour and policies: they are not automatic. Others place their faith in technology. Past predictions of famine caused by population explosion have been circumvented by increasing crop yields, but that does not mean we can assume they can be raised indefinitely. Neither complexity nor overconfidence should be an excuse for inaction.

Others argue, with good cause, that the real problem is consumption, not how many humans are walking the Earth. The World Bank estimates that 1.3 billion people are trapped in absolute poverty, living on $1.25 (80p) a day or less. And yet we Westerners consume more than our "fair share". Of course, we cannot discuss one without the other. When we consider population size, we must assess not merely the minimum that humanity needs for survival, but how much is needed for every individual to flourish. With even the most generous of arithmetic it is clear that the planet cannot support ever-increasing numbers at ever higher levels of consumption.

A family receives family planning advice at Kivunge Hospital, Zanzibar.
A family receives family planning advice at Kivunge Hospital, Zanzibar. Photo © Sala Lewis/UNFPA

There are no quick fixes, but that does not mean that we can ignore it. Although science cannot provide all the solutions, it does have a key role to play. During my lifetime, science has made huge strides in addressing humanity's great challenges: new methods of energy generation, for example, bring electricity to people in deprived areas.

But great as these achievements are, science is not the whole story. We need socio-economic structures that distribute goods more fairly, reducing the damaging effects of excessive consumption in the rich countries and lifting the least developed out of poverty. We need to provide universal education that empowers young people to take control of their lives and bodies. Through education and the provision of reproductive health and family planning services women can choose to have fewer, healthier, thriving children. Yet 215 million women around the world still lack the basic right to choose when to have children and their desired family size.

There is no excuse for getting this wrong. Of all the species on Earth, we are the one that has the ability to think beyond the present, to communicate and to plan. Surely we have the nous to put our affairs in order and avoid the vast human tragedy of population boom and bust?  

This is a slightly shortened version of an article which first appeared in The Times earlier this month.

Visit the Royal Society's People & the Planet project.