Our population has tripled within less than one generation. The major reasons are the crash in death rates as a consequence of controlling infectious disease, higher life-expectancy and better quality of life. We are projected to add another 3 billion by 2050; that is more than Europe, Africa, and both Americas combined. It is not about people having huge families, it is about one billion teenagers reaching reproductive age. If we keep this growth trend, human inequality and suffering will only increase, without mentioning the impact on the environment. We are the most intelligent species on the planet and we have a moral obligation to care for it.

Approximately 2 people are born every second, 200,000 every day, and 80 million every year. All need access to limited resources such as food, shelter, energy and water. Our history has been to overcome such limitations which, in other species, naturally balance out their relative abundance.

Population growth is often an ignored issue because it infringes on one of our most personal choices. This neglect puts our species at peril. The Earth has supported us so far; as we grew, we exploited its resources more effectively. Today, we are reaching its limits. Indeed, human density is a factor in any environmental issue. 1.3 billion people already lack access to clean drinking water, we have to double food production by the end of the century, and oil demand is predicted to rise by 40% within the next two decades.

Rwanda’s population is growing at a huge speed; it is predicted to double in 26 years. As 80% subsist on what they can grow, experts believe the genocide was strongly related to a too dense population and competition for scarce resources. Are we reaching our carrying capacity? William Rees has applied this ecological concept to man. He stresses that it totally depends on lifestyle. He has worked out the “productive bio-capacity” of the earth, measured as “global hectares (gh)”. If we were to share this productivity evenly, there would be circa 2 gh per capita per year. But the reality is very different: Africa uses just above half of that share, the average Indian uses less than half, but Europe uses 4.55 gh with the UK on top averaging 5.33! The US use over 4 times their fair share.

So, if all humans lived like the average Indian, the Earth could support 15 billion people, and up to 18 billion if we consumed like the average Rwandan, but only 2.5 billion with the UK living standard and 1.5 billion with the American standards! Yet the picture may be even darker, since these calculations assume the availability of resource levels that are thought not to be sustainable for the near future.

We currently consume 1.5 ‘Earths’ in terms of sustainable capacity. Even in terms of waste degradation, the Earth cannot keep up! A good example is Poland’s landfill mountains. People in developed countries need to give up a great deal of their consumption to give the ecological space for the needed growth in the Third World.

For example, it takes as much as 8,000 litres of water to produce a hamburger and 3,000 litres to produce a shirt – we can choose a path with a smaller footprint. Evidently, we must also switch to efficient and renewable technologies. But how to legally restrict the number of children a couple is allowed to have?

China introduced its successful One Child policy in 1979, following decades of famine. In 1977’s India however, Indira Gandhi introduced a “crisis program”: the penalisation for any crime was sterilisation. That year only, 8 million people were sterilised. Strong revolts brought the government down. This shows how easily perverted legal restrictions may be.

But there are other ways: educated women often choose to have fewer kids as they marry later. In Kerala, India, 1.5 children per household is standard. Unsurprisingly, the region has India’s highest literacy rates, and the average marriage age is 28 in contrast with 18 across the rest of India. On top of enhanced education, contraception can perhaps also be used as a powerful technology to solve the population problem.