The world has a lot of problems. An exploding population isn't one of them.
Ever since Parson Thomas Robert Malthus wrote his 1798 essay on population, it has been trotted out by millenarians and self-styled Cassandras as the basis for predicting famine and global woe. Malthus's arguments were resurrected as a best-seller for the modern era in the 1968 overpopulation-panic classic The Population Bomb. More recently, Columbia University economist Jeffrey Sachs has cited Malthus to explain the dire state of Africa, and Harvard University historian Niall Ferguson to predict a coming 20 years of global misery. The recent food crisis -- which pushed 100 million-plus people worldwide into absolute poverty -- has elevated Malthus's reputation as a prognosticator to the Delphic levels of a Nostradamus or an Al Roker.
But despite his centuries-long global celebrity and recent revival, the parson's predictions have been wrong from the start. He was wrong about the future of his native Britain. And he was wrong about the future of everywhere else.
Malthus's argument, laid out in his Essay on the Principle of Population, begins with condescending absolutism: The quantity of land is the ultimate arbiter of how much can be produced, and the unwashed masses will always breed until they've used up the maximum productive capacity of the land. This leaves populations condemned to live on subsistence incomes, with birth rates matched by death rates, in turn determined by the difficulty of acquiring food. The only way to improve lives, Malthus concludes, is to shrink population sizes. Offering relief to the poor simply creates more miserable paupers.
Within Malthus's lifetime, however, the quantity of land stopped being the primary determinant of a country's output: We began making a lot more stuff in a lot less space. The world's output in 1820 was smaller than South Korea's GDP today, according to statistics from British economist Angus Maddison. Global agricultural output has tripled since 1950 alone, while global GDP has increased eightfold. Out of 140 economies tracked by Maddison between 1950 and 2000, all expanded, and only four didn't at least double in size. Eighty-eight percent saw rising incomes per capita (so much for a subsistence income), and none saw a decline in population. All those extra people can't eat the industrial and services output that accounts for the majority of GDP growth, of course. But with the money they make, they can tap into what is now a $600 billion global trade in agriculture.
As for the fertility habits of poor people, John Stuart Mill was pointing out by the mid-19th century that Western European incomes were rising while population growth rates were shrinking in a most un-Malthusian manner. And that pattern, too, has spread worldwide. Between 1960 and 2000, fertility rates fell in all but four of 187 countries for which we have data. The average decline was 42 percent. Improved child health has been a particularly powerful force behind lower fertility rates -- despite Malthus's skepticism that lower child mortality would play any role in escaping the subsistence trap.
But what about the future? Won't Malthus eventually get the last laugh? Don't bet on it. Food prices have risen in the last couple of years, but not because we're reaching the limits of our productive capacity to prevent global starvation. The largest factor behind recent price increases is U.S. subsidies that divert 80 million-plus tons of corn into ethanol production each year, World Bank economist Donald Mitchell has calculated. And though today's global population of 6.8 billion is more than nine times what it was at Malthus's birth, experts reckon we could support a population that's twice as big or more without running out of food. Indeed, 1.6 billion people on the planet today are overweight -- far more than the 1 billion who are undernourished. And the ubiquitous decline in fertility worldwide suggests, pace Malthus, that giving poor people a little more money really would permanently reduce the number of malnourished.
Lately, the Malthusian cart has been hitched to the horse of global environmental sustainability. As Population Bomb author Paul Ehrlich phrased it, "The overriding reason to care about the population explosion is its … impact on the environmental systems that support civilization." Malthus's model suggests the solution to the world's problems is to stop the poor from breeding. But if you are concerned about overconsumption, that's absolutely the wrong place to start. The planet's poorest 10 percent receives only 0.6 percent of the world's income. And sub-Saharan Africa's population accounts for about 2 percent of global carbon dioxide emissions. So if you want to slow climate change through population control, don't look to Niger or Mali; Donald Trump and the rest of the Forbes rich list should be first to the vasectomy table.
Malthus's ideas weren't entirely unconstructive -- he believed civil liberties and education were key to improving the lives of the poor, for example. And no matter how flawed their logic, modern-day Malthusians such as Sachs back a range of good policies, such as ensuring widespread access to safe and effective birth control (a fix Malthus thought immoral). But the dystopian model at the core of Malthusianism is way off base. If impending disaster is what it takes to get us off the couch, there are plenty of urgent catastrophes to worry about. The two-century-old musings of a gloomy English parish priest shouldn't be among them.
PHOTO ILLUSTRATION BY WIND-UP STUDIOS; IMAGE, CORBIS