Overpopulation remains the leading driver of hunger, desertification, species depletion and a range of social maladies across the planet. Recently, a spate of op-ed essays have filled the pages of some of world's top newspapers and blogs -- from the Guardian to the New York Times -- challenged this view, declaring that overpopulations is not, nor has ever been, a problem. To make progress in the most recent round of the age-old debate between technological optimists and Malthusian realists, it's important to establish criteria and characterize consequences.
On what basis are these newest cornucopian assurances made? In the New York Times piece, for instance, Ellis Erle asserts that after studying the ecology of agriculture in China and talking to archaeologists, he reached the conclusion that technologies have always been able to overcome any anticipated exceedance of carrying capacity. A key corroboration marshaled for this view refers to a retrospective assessment of Chinese farming by archaeologists. It purportedly claims that new and more efficient technologies invariably enabled local farmers to overcome any anticipated exceedance of carrying capacity.
If food security is the criterion, it is particularly ironic that arguments are based on China. Anyone with a teaspoon of historic sensibilities about the country's environmental history might want to mention its long litany of famines which occurred precisely because carrying capacities were consistently outstripped by a growing population.
Conservative estimates report that China's most recent food crisis, between 1958 and 1961, led to the starvation of over twenty million people, in part due to the erosion of China's natural capital. Uncontrolled human fertility led to a depletion of the land's fertility. Previous famines were worse. Over the years, hundreds of millions died a horrible death of hunger. Their misery should teach a sobering lesson about insouciant disregard for the balance between human numbers and natural resources.
Chinese one-child policy has been tough medicine, and implementation was clearly flawed. But it also prevented the next round of famines that would have taken far more lives had China continued to race forward and became a nation of two billion. Even so, China today still needs to bolster local food supply by attaining lands overseas.
It gives little satisfaction for sustainable population advocates to point out that the past twenty years saw an estimated 200 million hunger-related deaths worldwide. Relatively few occurred in countries where population was stable. The U.N. reports that today one in eight people in the world suffers chronic undernourishment. Almost without exception, they live in developing regions, where most of the planet's population growth continues apace. If family planning had been energetically promoted years ago, enormous suffering could have been avoided.
Present global trends will lead to a doubling of the world's urban areas by 2050. That means that cities, mostly in developing countries, will expand from 3 to 6 percent of all-ice free land. It also means that 10 to 15 percent of lands farmed today would be taken out of production. In a perfect world we would have better ways of distributing surplus food to famine stricken regions or promoting land reform to optimize food production. But for the foreseeable future we will be living in a very imperfect world where communities need to take care of themselves and maintain sustainable populations.
Overpopulation is not just about food shortages and human suffering. Ecologists explain that the collapse in global biodiversity is also linked to overpopulation. China, Mexico and Brazil have been singled out as extreme cases of species loss. Brazil's population grew four fold during the past sixty years; little wonder the Amazon is feeling the pressure. Mexico and China's growth is comparable.
Israel offers a microcosm of the global situation: A meeting point of three continents, at the middle of the twentieth century, this tiny country was still home to an astonishing assemblage of mammals, birds and reptiles. That's because in 1949 there were one million people living in Israel. Today there are eight million. The equation is simple: more people means less wildlife. Accordingly, about a third of the country's 115 indigenous mammal species today are either endangered or critically endangered. The amphibian population is almost entirely extirpated.
Israel has a remarkable program of conservation and its powerful Nature and Parks Authority set aside 25% of the country for reserves. But growing human settlement continues to fragment habitats and undermine the benefits that nature provides. These go far beyond any individual organism. When humans encroach on open spaces, they also lose the free services that nature provides: filters for clean water, protection from hurricanes, natural pollinators, soil integrity and recreational resources. The rapid rise in populations also tends to sabotage basic social services: schools are crowded, medical care overwhelmed, the legal system backed up, transportation gridlock unbearable and accessible housing inadequate. Infrastructure has a very hard keeping up with relentless growth.
Technological Pollyannas suggest that today's technologies mean that we in the West needn't be concerned. But of course we should. There are global limits that affect us all. Even Israel, whose ultra-hi-tech agriculture probably yields more "crop per drop" than any other country is only able to produce 45% of the calories required for its growing population.
The good news is that public policy matters and can reduce overpopulation. Many countries, from Bangladesh and Iran to Singapore and Thailand adopted policies that incentify small families, make birth control available, provide better social security and most of all -- empower women. The results are remarkable, showing that trend need not be destiny. As population began to stabilize, the drop in undernourished people in Asia and the Pacific went down from 23.7 percent to 13.9 percent. The quality of education, housing and health improved as a matter course.
It is time to realize that there is a tradeoff between "quality of life" and "quantity of life." In a planet with limited resources -- sustainable growth is an oxymoron. Of course humanity could all shift to vegan diets, forgo national parks and crowd in a few more billion people, hoping that new levels of efficiency will allow us to survive. But it is well to ask if this really is the kind of world that we want? There is much we can do to reduce the suffering caused by human population growth. But recognizing that overpopulation is a perilous problem constitutes a critical first step.