It’s easy to grasp that in a national park, balance must be maintained between predators and prey, lest the ecosystem crash. But when we’re talking about our own species, it gets harder. The notion that there are limits to how much humanity this parkland called Earth can bear doesn’t sit easy with us.
The “nature” part of human nature includes making more copies of ourselves, to ensure our genetic and cultural survival. As that instinct comes in handy for building mighty nations and dominant religions, we’ve set about filling the Earth, rarely worrying that it might one day overfill. Even after population quadrupled in the 20th century, placing unprecedented stress on the planet, it’s hard for some to accept that there might be too many of us for our own good.
A recent essay in the New York Times by University of Maryland geographer Erle C. Ellis, argued that population growth is actually the mother of invention, that it inspires new technologies to sustain ever more humans and to coax more from the land. And as Pope Benedict XVI wrote in his 2009 encyclical “Caritas in Veritate,” “On this Earth there is room for everyone … through hard work and creativity.”
In 2011, I visited the Vatican’s Pontifical Academy of Sciences, which had warned in 1994 that it was “unthinkable to sustain indefinitely a birthrate beyond 2.3 children per couple…. The contrary demographic consequences would be unsustainable to the point of absurdity.” Nevertheless, the church still encouraged population growth.
With a billion humans already malnourished, I asked the academy’s director where would we get food for nearly 10 billion by midcentury? Clearing more forests for farming would be disastrous. Beset by floods and erosion, China alone has been spending $40 billion to put trees back. And force-feeding crops with chemistry has backfired on us, with nitrogen runoff that fouls rivers, deadens New Jersey-sized chunks of the oceans and emits large quantities of two greenhouse gases: carbon dioxide and nitrous oxide.
The answer, I was told, would be through increased yields using new genetically modified crops from the centers of the Green Revolution: the International Maize and Wheat Improvement Center in Texcoco, Mexico, and the International Rice Research Institute in the Philippines.
The Green Revolution’s high-yield, genetically selected strains more than doubled grain harvests during the 1960s. It is often cited as having triumphed over dire predictions of famines caused by population growth outpacing food production, which were famously made by economist Thomas Robert Malthus in “An Essay on the Principle of Population” and echoed by his latter-day analogues, Paul and Anne Ehrlich, who wrote “The Population Bomb.”
However, when I went to the maize center in Texcoco and to the rice institute in the Philippines, I found no food scientists who agreed with that triumphalist scenario. Instead, I learned, Green Revolution founder Norman Borlaug had warned in his 1970 Nobel Peace Prize acceptance speech that his work essentially had only bought the world time to resolve overpopulation.