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It’s been 41 years since Paul Ehrlich predicted imminent mass starvation, in his 1968 jeremiad, The Population Bomb. In the years that followed, a green revolution drove crop production rapidly upward, while population growth slowed dramatically; Ehrlich’s bomb, rather conspicuously, failed to go off.
Nonetheless, we’re still multiplying—global population is on track to reach 9.1 billion by 2050, up from 6.8 billion today. And the green revolution seems to have run its course: rice yields, for instance, are growing at only 1 percent a year, down from 2.3 percent in the 1960s, 1970s, and 1980s. For the past several years, grain production has not kept up with demand; if we are to put enough food on the table in the coming decades, something big will need to change.
Much of the world’s arable land is being farmed already, so the lion’s share of the increase will need to come through higher yields. In many places, yields can increase—if prices rise high enough to make investment in more-intensive agriculture worthwhile. Still, much of the developed world is approaching the ceiling of what is cheaply possible. Sub-Saharan Africa, despite its long history of food insecurity, is one place where yields could increase dramatically; agricultural basics such as good seed and fertilizer would go far in a region that the green revolution bypassed. “We could increase yields in sub-Saharan Africa threefold tomorrow with off-the-shelf technology,” says Kenneth Cassman, a well-regarded agronomist who researches potential yields. The problem is the continent’s long history of corruption, poor infrastructure, and lack of market access.