Even when we try to adapt, we move too slowly. Economist Richard Hornbeck specializes in the history of the American Dust Bowl; he says that farmers of that era could conceivably have adapted to the changing climate of their time by cultivating different crops. But they didn’t, lacking credit to make the necessary investments—and were therefore unable to shake inertia and ritual and the rootedness of identity. So instead the crops died out, in cascading waves crashing through whole American states and all the people living in them.
As it happens, a similar transformation is unfolding in the American West right now. In 1879, the naturalist John Wesley Powell, who spent his downtime as a soldier during the Battle of Vicksburg studying the rocks that filled the Union trenches, divined a natural boundary running due north along the 100th meridian. It separated the humid—and therefore cultivatable—natural farmland of what became the Midwest from the arid, spectacular, but less farmable land of the true West. The divide ran through Texas, Oklahoma, Kansas, Nebraska, and the Dakotas, and stretches south into Mexico and north into Manitoba, Canada, separating more densely populated communities full of large farms from sparser, open land that was never truly made valuable by agriculture. Since just 1980, that boundary has moved fully 140 miles east, almost to the 98th parallel, drying up hundreds of thousands of square miles of farmland in the process. The planet’s only other similar boundary is the one separating the Sahara desert from the rest of Africa. That desert has expanded by 10 percent, too; in the winter, the figure is 18 percent.
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The privileged children of the industrialized West have long laughed at the predictions of Thomas Malthus, the British economist who believed that long-term economic growth was impossible, since each bumper crop or episode of growth would ultimately produce more children to consume or absorb it—and as a result the size of any population, including that of the planet as a whole, was a check against material well-being. In 1968, Paul Ehrlich made a similar warning, updated for a twenty-first-century planet with many times more people on it, with his widely derided The Population Bomb, which proposed that the economic and agricultural productivity of the earth had already reached its natural limit—and which was published, as it happened, just as the productivity gains from what’s called the “green revolution” were coming into focus. That term, which today is sometimes used to describe advances in clean energy, first arose to name the incredible boom in agricultural yields produced by innovations in farming practices in the middle of the twentieth century. In the half century since, not only has the world’s population doubled but the fraction of people living in extreme poverty has fallen by a factor of about six—from just more than half of humanity to 10 percent. In the world’s developing countries, undernourishment has dropped from more than 30 percent in 1970 to close to 10 percent today.
These developments counsel sanguinity in the face of all kinds of environmental pressures, and in his recent book on the meaning of the twentieth-century agricultural boom, the writer Charles Mann divides those who respond to the seeming challenge of resource scarcity with reflexive optimism, whom he calls “wizards,” from those who see collapse always around the corner, whom he calls “prophets.” But though the green revolution seems almost too perfectly conceived and executed to refute Ehrlich’s alarmism, Mann himself is not sure what the lessons are. It may yet be a bit early to judge Ehrlich—or perhaps even his godfather, Malthus—since nearly all of the astonishing productivity gains of the last century trace back to the work of a single man, Norman Borlaug, perhaps the best argument for the humanitarian virtue of America’s imperial century. Born to Iowa family farmers in 1914, he went to state school, found work at DuPont, and then, with the help of the Rockefeller Foundation, developed a new collection of high-yield, disease-resistant wheat varieties that are now credited with saving the lives of a billion people worldwide. Of course, if those gains were a onetime boost—engineered, in large part, by a single man—how comfortably can we count on future improvements?
The academic term for the subject of this debate is “carrying capacity”: How much population can a given environment ultimately support before collapsing or degrading from overuse? But it is one thing to consider what might be the maximum yield of a particular plot of earth and another to contemplate how fully that number is governed by environmental systems—systems far larger and more diffusely determined than even an imperial wizard like Borlaug could reasonably expect to command and control. Global warming, in other words, is more than just one input in an equation to determine carrying capacity; it is the set of conditions under which all of our experiments to improve that capacity will be conducted. In this way, climate change appears to be not merely one challenge among many facing a planet already struggling with civil strife and war and horrifying inequality and far too many other insoluble hardships to iterate, but the all-encompassing stage on which all those challenges will be met—a whole sphere, in other words, which literally contains within it all of the world’s future problems and all of its possible solutions.
Curiously, maddeningly, these can be the same. The graphs that show so much recent progress in the developing world—on poverty, on hunger, on education and infant mortality and life expectancy and gender relations and more—are, practically speaking, the same graphs that trace the dramatic rise in global carbon emissions that has brought the planet to the brink of overall catastrophe. This is one aspect of what is meant by the term “climate justice.” Not only is it undeniably the case that the cruelest impacts of climate change will be borne by those least resilient in the face of climate tragedy, but to a large degree what could be called the humanitarian growth of the developing world’s middle class since the end of the Cold War has been paid for by fossil-fuel-driven industrialization—an investment in the well-being of the global south made by mortgaging the ecological future of the planet.
This is one reason that our global climate fate will be shaped so overwhelmingly by the development patterns of China and India, who have the tragic burden of trying to bring many hundreds of millions more into the global middle class while knowing that the easy paths taken by the nations that industrialized in the nineteenth and even twentieth centuries are now paths to climate chaos. Which is not to say they won’t follow them anyway: by 2050, milk consumption in China is expected to grow to triple the current level, thanks to the changing, West-facing tastes of its emerging consumer classes, a single-item boom in a single country that is expected, all by itself, to increase global greenhouse-gas emissions from dairy farming by about 35 percent.
Already, global food production accounts for about a third of all emissions. To avoid dangerous climate change, Greenpeace has estimated that the world needs to cut its meat and dairy consumption in half by 2050; everything we know about what happens when countries get wealthier suggests this will be close to impossible. And turning away from milk is one thing; turning down cheap electrification, automobile culture, or the protein-heavy diets the world’s wealthy rely on to stay thin are much bigger asks. In the postindustrial West, we try not to think about these bargains, which have benefited us so enormously. When we do, it is often in the guilty spirit of what critic Kris Bartkus has memorably called “the Malthusian tragic”—namely, our inability to see any remaining innocence in the quotidian life of the well-to-do West, given the devastation that wealth has imposed on the world of natural wonder it conquered and the suffering of those, elsewhere on the planet, left behind in the race to endless material comforts. And asked, functionally, to pay for them.