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.