Our Uncrowded Planet
Thursday, October 1, 2009
Imminent doom has been declared again. But don’t worry, neo-Malthusian predictions of overpopulation are wrong.
Every so often, the overpopulation meme erupts into public discourse and imminent doom is declared again. A particularly overwrought example of the overpopulation meme and its alleged problems appeared recently in the Wall Street Journal’s MarketWatch in a piece by regular financial columnist Paul B. Farrell.
Farrell asserts that overpopulation is “the biggest time-bomb for Obama, America, capitalism, the world.” Bigger than global warming, poverty, or peak oil. Overpopulation will end capitalism and maybe even destroy modern civilization. As evidence, Farrell cites what he calls neo-Malthusian biologist Jared Diamond's 12-factor equation of population doom.
It turns out that Farrell is wrong or misleading about the environmental and human effects of all 12 factors he cites. Let’s take them one by one.
1. Overpopulation multiplier: Looking at the most recent United Nations’ population projections, it is likely that world population will peak somewhere between 8 and 9 billion near the middle of this century (current population is about 6.8 billion) and then begin declining back toward 6 billion by 2100. In addition, if lower fertility rates are the goal, promoting economic freedom is the way to achieve it. In 2002, Seth Norton, a business economics professor at Wheaton College in Illinois, published a remarkably interesting study on the inverse relationship between economic freedom and fertility. Norton found that the fertility rate in countries that ranked low on economic freedom averaged 4.27 children per woman while countries with high economic freedom rankings had an average fertility rate of 1.82 children per woman.
Crop yields have been increasing at a rate of about 2 percent year for 100 years and now population is growing at 1 percent per year.
2. Population Impact multiplier: Farrell mirrors Diamond's concern that the world's poor want to become rich. This means that they aim to consume more. Can the Earth sustain increased consumption? Yes, economic efficiency is dematerializing the economy and thus will spare more land and other resources for nature. As Jesse Ausubel, director of the human environment program at Rockefeller University, and colleagues have shown, although the average global consumer enjoyed 45 percent more affluence in 2006 than in 1980, each consumed only 22 percent more crops and 13 percent more energy. See below for more information on positive trends in agriculture, water usage, and forest growth.
3. Food: Farrell says we are running out. It is true that far too many people are on the verge of starvation and the recent economic crisis has pushed even more in that direction. But Farrell and Diamond overlook the fact that crop yields have been increasing at a rate of about 2 percent per year for 100 years and now population is growing at 1 percent per year. Agronomist Paul Waggoner argued in his a 1996 article, "How Much Land Can Ten Billion People Spare for Nature?," published in the journal Daedalus, that "if during the next sixty to seventy years the world farmer reaches the average yield of today’s U.S. corn grower, the 10 billion will need only half of today’s cropland while they eat today’s American calories." If Waggoner is right—and all signs are that he is—the future will be populated by fat people who will have plenty of wilderness in which to frolic.
4. Water: There is no doubt that a lot of fresh water is being wasted. However, we know how to solve that problem—create property rights and free markets for water. For example, water use per capita in the United States has been declining for two decades. Farrell and Diamond propagate the stale water wars meme. Transboundary water cooperation rather than conflict is the norm. "The simple explanation is that water is simply too important to fight over," notes Aaron Wolf, the Oregon State University professor who heads up the Program in Water Conflict Management. Wolf observes that history records that the last water war occurred 4500 years ago between Lagash and Umma over irrigation rights in what is now Iraq.
Farrell claims that forests are being destroyed at an accelerating rate. He is wrong. Forest regrowth is the actual trend in many places.
5. Farmland: First note that vast increases in agricultural productivity over the past half century spared an area about the size of South America from being plowed up to produce food for the current population. In a 2000 Science article, soil scientist Pierre Crosson and colleagues noted, "studies of the onfarm productivity effects based on 1982 N[ational] R[esource] I[nventory] cropland erosion indicated that if those rates continue for 100 years, crop yields (output per hectare) would be reduced only 2 to 4 percent. These results indicate that the productivity effects of soil erosion are not significant enough to justify increased federal outlays to reduce the erosion, but not all agree." In any case, soil erosion is a problem that is being addressed by modern high-tech no-till agriculture.
6. Forests: Farrell claims that forests are being destroyed at an accelerating rate. He is wrong. Forest regrowth is the actual trend in many places. A 2006 article on forest trends in the Proceedings of the National Academy of Sciences found "Among 50 nations with extensive forests reported in the Food and Agriculture Organization’s comprehensive Global Forest Resources Assessment 2005, no nation where annual per capita gross domestic product exceeded $4,600 had a negative rate of growing stock change." In fact, leaving aside Brazil and Indonesia, globally the forests of the world increased by about 2 percent since 1990. And there is further good news—a quarter to a third of the tropical forests that have been cut down are now regenerating.
7. Toxic chemicals: Farrell writes, "Consider the deadly impact of insecticides, pesticides, herbicides, detergents, plastics ... the list is endless." When one actually considers the impact on synthetic chemicals on people, it turns out that the more man-made chemicals, the higher do human life expectancies rise. Contrary to activist claims, trace amounts of synthetic chemicals are not producing a cancer epidemic. In fact, cancer incidence rates in the U.S. have been falling for nearly a decade.
8. Energy resources, oil, natural gas, and coal: Farrell is just incoherent here. He hints at "peak oil," and supplies may become tight, but that would largely be a result of political factors, not the depletion of reserves. As for coal and natural gas supplies, no one is suggesting their imminent depletion.
9. Solar energy: Farrell does not here mean photovoltaic power, but rather the Earth's "photosynthetic capacity,” that is, the ability of plants to turn sunlight into food, fuel, and other useful products. Apparently, he thinks that humanity is using too much of it. To the extent this is a problem, biotech advances are already addressing it by researching ways to boost crop productivity by transforming plants from less efficient C3 photosynthesizers to the more efficient C4 pathway.
The world's poor want to become rich. This means that they aim to consume more. Can the Earth sustain increased consumption? Yes.
10. Ozone layer: Farrell seems unaware of the fact that this problem has already largely been dealt with. To the extent this was a problem, the Montreal Protocol in 1987 that banned the refrigerants that were depleting the ozone layer has fixed it. This month, NASA reported a slightly positive trend of ozone increase of almost 1 percent per decade in the total ozone from the past 14 years.
11. Diversity: Biodiversity trends are notoriously difficult to predict. In 1979, Oxford University biologist Norman Myers suggested in his book The Sinking Ark that 40,000 species per year were going extinct and that 1 million species would be gone by the year 2000. Myers suggested that the world could "lose one-quarter of all species by the year 2000." At a 1979 symposium at Brigham Young University, Thomas Lovejoy, former president of The H. John Heinz III Center for Science, Economics, and the Environment announced that he had made "an estimate of extinctions that will take place between now and the end of the century. Attempting to be conservative wherever possible, I still came up with a reduction of global diversity between one-seventh and one-fifth." Lovejoy drew up the first projections of global extinction rates for the “Global 2000 Report to the President” in 1980. If Lovejoy had been right, between 15 and 20 percent of all species alive in 1980 would be extinct right now. No one believes that extinctions of this magnitude have occurred over the last three decades.
What happens to humanity if many species do go extinct? In a 2003 Science article called "Prospects for Biodiversity,” Martin Jenkins, who works for the United Nations Environment Programme-World Conservation Monitoring Center, pointed out that even if the dire projections of extinction rates being made by conservation advocates are correct, they "will not, in themselves, threaten the survival of humans as a species." The Science article notes, "In truth, ecologists and conservationists have struggled to demonstrate the increased material benefits to humans of 'intact' wild systems over largely anthropogenic ones [like farms] … Where increased benefits of natural systems have been shown, they are usually marginal and local."
12. Alien species: Farrell claims, "transferring species to lands where they're not native can have unintended and catastrophic effects." Mostly not. Biologist Mark Davis chalks up most opposition to "alien" species to prejudice and muddy thinking, adding in the current issue of the New Scientist that "you may be surprised to learn that only a few per cent of introduced species are harmful. Most are relatively benign." As I pointed out nine years ago, the preference for native over non-native species is essentially a religious one. It has no warrant in biology.
While there certainly are environmental problems, current trends do not portend a looming population apocalypse. Instead, the 21st century will be more likely remembered as the century of ecological restoration.
Ronald Bailey is Reason magazine's science correspondent.
FURTHER READING: Bailey’s book Liberation Biology: The Scientific and Moral Case for the Biotech Revolution is now available from Prometheus Books.
Image by Darren Wamboldt/Bergman Group.