Monday, October 24, 2011

Welcome to Earth, Population: 7 Billion

This month, the global population will surpass 7 billion people, for the first time in history. Predictably, this milestone has sparked a discussion of overpopulation and sustainability. Pessimists are quick to point to the historical trend. Two thousand years ago, the global population was a mere 200 million people. Even by 1900, there were only 1.6 billion of us. But during the 20th century, population growth exploded as modern medicine dramatically increased life expectancies all across the world. Even people in the shortest-lived countries today (Afghanistan and Zimbabwe) live longer than those in the longest-lived countries did in 1800 (United Kingdom and Netherlands).

The unfortunate side effect of that amazing record of progress has been an ever-increasing population, consuming more and more resources from our planet. Many have questioned how long this can continue. As early as 1798, Thomas Malthus argued that growth in population was outstripping growth in the food supply, and this would inevitably result in widespread famine. In 1968, Paul Ehrlich wrote The Population Bomb, which predicted that overpopulation would soon cause mass starvation, destroy the environment, and lead to widespread war.

So far these predictions have failed to materialize, and it is unlikely that they ever will. Concerns of global overpopulation are overblown. There is plenty of room for everyone; we could fit the entire world’s population into the state of Texas, and the population density would be no greater than New York City. On the question of food security, the Malthusian predictions have always failed to take into account technological development. When Malthus made his original prediction, he completely overlooked the Industrial Revolution that was beginning to unfold around him, making the production of food much more efficient. When Ehrlich did the same, he overlooked both the Green Revolution that increased the production of food threefold, and the invention of new birth control technologies which reduced the rate of growth in the population.

In fact, population growth peaked in 1968, just as The Population Bomb was hitting bookshelves. Although it has not yet stabilized, the rate of growth continues to decline. Some parts of the world are already losing people; the fertility rates in Europe, Russia, and East Asia are well below the replacement rate. The United Nations projects that the global population will plateau by the end of this century, between 10 and 15 billion people.

Even the upper end of the UN’s projection is not unsustainable; if we have 15 billion people by the end of this century, we will easily be able to feed them all, with plenty of food to spare. The population doomsayers will continue to be wrong for the same reason that Malthus and Ehrlich were wrong: they ignore technological developments that allow the production of much more food. The coming Genomic Revolution will play a huge role in this process. Not only will it soon be possible to genetically engineer crops that produce a much higher yield in a given amount of space, it will also be possible to breed crops that can grow in much harsher climates than is currently possible, allowing for the widespread production of crops in parts of the world that were previously considered off-limits. The drought-ravaged Sahel Zone of Africa could one day be a breadbasket. Cold climates like Canada and Russia may one day be able to grow coffee.

Additionally, the development of in vitro meat production will soon mean that it is no longer necessary to raise large herds of livestock when meat can be more efficiently grown in a laboratory. This will free up a huge amount of the earth’s farmland and fresh water, which would otherwise be required to feed the animals. These technological developments – as well as others which may not even be anticipated yet – will undoubtedly allow us to continue feeding our growing global society.

Although global overpopulation is not a problem, the problems of specific regions of the world should not be minimized. South Asia is the hardest hit by overpopulation. India has 1.2 billion people crammed into an area one-third the size of the United States. Bangladesh has 150 million (half the population of the US) packed in an area smaller than Florida. In both of these cases, the vast majority of people live in crushing poverty, with some of the highest rates of malnourishment anywhere in the world. But even here, there is some good news. Both India and Bangladesh have taken steps to get their fertility rates under control, and now their fertility rates are only slightly above the replacement rate of 2.1 children per woman. The era of rapid population growth is drawing to a close for South Asia, although it will still take several decades before it levels off completely.

Many Sub-Saharan African countries have a demographic problem as well, although the nature of the problem is different from South Asia’s problem. With a few exceptions, Africa is not particularly densely populated. Some UN officials and developmental economists have even gone so far as to argue that many parts of Sub-Saharan Africa are underpopulated. I think that’s a bit of an exaggeration for a region of the world that cannot currently feed itself, but there is no denying that Africa’s population is nowhere nearly as densely populated as South Asia. India alone has more people than the entire African continent. Africa’s demographic problem is the rapid rate of growth in its population. Unlike India and Bangladesh, which have finally gotten their growth rates under control, many African nations still have fertility rates as shockingly high as 4 or more children per woman. In the case of Niger, the fastest-growing country in the world, women have 7.6 children on average. In other words, the problem facing many Sub-Saharan African nations is that their population is growing faster than their ability to provide for their people.

Can Africa’s demographic problem be solved? Of course. High fertility rates are closely linked to poverty. Families tend to have more children in societies where the opportunity cost of having kids is low, where children can assist with subsistence farming, and where infant mortality rates are high enough that having extra children provides a hedge against the tragic risk that some of them will not survive to adulthood. As Sub-Saharan African countries continue to develop their economies, these underlying problems will fade away just as they did in South Asia and Latin America, and fertility rates will drop. This issue has been widely studied by developmental economists, who have concluded that the best ways to reduce fertility rates are to ensure access to cheap birth control, improve education (especially for girls), and improve health care and nutrition for infants. Many African nations are making tremendous progress toward these goals, and are already seeing the dividends in reduced fertility rates.

So when our global population officially hits the 7 billion mark this week, remember to take the doomsayers with a grain of salt. Our planet is not overpopulated. At the present time, it is a localized problem for only a couple regions of the globe, and soon it will not be a problem at all. Our economic and technological development will see to that. There is plenty of room on our pale blue dot for more people.