A wit said to me ‘people think population is like a party – the more the better’. But what if the beer runs out? What if the empties start piling up round our chin? What if the queue for the toilet gets so long people are busting?

When Easter Island was discovered by Westerners it was treeless, but contained evidence that it had hosted not only forests but an advanced Polynesian civilisation, by then nearly extinct.

An extra 2 to 3 billion people will be living on the planet in five decades time. There’s already 6.8 billion of us. Will 9 and a bit billion be a problem?

None of these are likely in the short term: a shortage of food; of space; of water; of oxygen; of fuel. Space remains abundant. Particular types of fuel may dry up, but the sun and the tides will replenish us. Water could be problematic, but rationing means it is unlikely to ever get critical. Beware extrapolation – humans are good at solving problems. Soylent Green remains fiction. Nevertheless, the World Wide Fund for Nature estimates we would need 3 planets if the world’s entire population had European living standards.

The problems of the global population may not be shortages but abundances. Humankind is, for the first time, dragging hundreds of millions out of poverty, and catapulting a proportion of those toward the kind of first-world affluence we take for granted. This is exciting. But simultaneous explosions in growth and wealth might create an abundance of waste:

Carbon pollution, sewage, rubbish, nuclear waste, and particle pollution.

One reason for being cautious about the environmental effects of population growth is explained by the concept of ecology – the interlinkages of natural systems. It was influential when it was developed. Regrettably, we have survived enough extinctions and environmental degradation by now that the fear of accidentally making our environment uninhabitable has less traction. But our dependence on air, soil and water mean conserving health of seas, rivers and forests is important. We are as isolated in space as Easter Island is in the Pacific. It would be tragic to see the example but not heed it.

We can and should act from a diversity of angles. Regulations, regulated markets for ‘bads’ (e.g. tradable carbon permits) and technical progress will all be important in capping the environmental impact of simultaneous explosions in growth and wealth.

No solution should countenance leaving individuals in dire poverty. If there is a limit to how many people may enjoy wealth, it is better that there be fewer individuals.

The only way to cut population is by influencing the birth rate. This raises a question of whether people have a right to have children. The answer must be yes. But not an unlimited right. If we agree there is a limit to growth (or a reasonable probability of a limit), then beyond a certain number, making babies will (or is likely to) inhibit someone else from enjoying their rights to clean air, water, a functioning ecology, etc. Conflicting rights mean action can justifiably be taken to try to shape people’s behaviour.

RESPONSES

Assume we think that the problems described are plausible, and the reasons to tackle them sound. What then?

China’s one-child policy is too harsh. It has been linked to forced abortion and infanticide. It reportedly applies to about 35 percent of the population and has brought the fertility rate to 1.8, from 2.9 in 1979. It would likely not work outside a repressive dictatorship, but, surprisingly, it is not a leading source of social discontent in that country, with 76 percent support. Many couples with exemptions from the policy have only one child for social reasons.

Will development do it?

“For the world as a whole, the number of children born per woman decreased from 5.02 to 2.65 between 1950 and 2005”

and

“The population of 51 countries or areas, including Germany, Italy, Japan and most of the successor States of the former Soviet Union, is expected to be lower in 2050 than in 2005.”

The problem for population control may not lack of incentive but lack of means:

The lack of access to contraception and abortion; and lack of power of women in much of the world means family planning is difficult or impossible. If these problems were tractable, population growth could be curbed without application of further incentives, at the same time as fostering self-determination in women.

PROBLEMS

Migration. Sadly, overpopulation may be addressed not for the reasons described above, but because the first world fears the migration flows that third world population growth could spark.

The population of Pakistan will go from 169 million now to 295 million in 2050. While many developed countries will stabilise, the poorest countries will grow fastest:

National population growth rates.

Coordination – Individual countries may not see the problem. Countries are individually stronger with more people. But the aggregate effect is to burden the globe, which is the ultimate closed system. Any meaningful population policy will have to be instituted globally. This means relying on the UN. hmm.

Benefits of many children In many poor countries, children are a source of material security for the family. They tend the crops and provide for their parents in their old age. Any global population policy could be seen as de facto discrimination. It’s easy for the first world to suggest such a policy, as it is less likely to affect their reproductive intentions. The benefits of this policy flow widely, but the majority of the change must be made by the poor. Any implementation would have to be broadly agreed and matched by targeted compensation, perhaps in the form of aid.

Too many Boys In China, all manner of social ills are predicted as a result of the gender imbalance that the one-child policy has produced. Including global war.

… and finally…. ‘Making predictions is hard. Especially about the future.’

Malthus was considered quite the visionary in the eighteenth century. He was worried about the global population when it rested at a mere billion, and predicted pereptual cycles of famine. He said:

“The constant effort towards population… increases the number of people before the means of subsistence are increased.”

Then he married his cousin.

More recently, Stanford population Professor Paul Ehrlich “predicted, in the late 1960s, that hundreds of millions would die from a coming overpopulation-crisis in the 1970s, and that by 1980 inhabitants of the United States would have a life-expectancy of only 42 years.”

Yeah, well.

Thoughts? Objections? Suggestions Corrections? Links? Funny youtube videos? Put them in the comments below!