Feeding the World

"At some point, you have to come down to a fundamental assumption that humans are ingenious," said Bill Easterling. "Historically, they've found a way to use resources so that those resources are rarely depleted."

farm house and field and trees
James Collins

Autumn paints the fields surroundings Rebersburg, Pennsylvania. Will the world's farmers be able to feed us all in 2050? And at what cost?

Easterling identifies himself as an optimist. So the conclusion of his lecture last January, on the effects of global warming on food security, sounded uncharacteristically pessimistic: "There will still be hungry people around in 50 years."

Easterling prides himself, as he puts it, "on trying to balance the often shrill viewpoints on whether global warming will take place and what its effects will be." Yet certain points are incontrovertible: Population is rising. "Some of us have lived through two doublings of Earth's population," Easterling noted. Six billion now, world population is expected to reach nine billion by 2050, and level off at ten to 11 billion by 2100. Seven billion will live in cities.

At the same time, the chemistry of Earth's atmosphere is changing. "Records put it beyond the shadow of a doubt that atmospheric concentration of carbon dioxide is increasing. Very few people question that this is not due to human action."

Finally, Earth is getting warmer. "Over the past 1,000 years, Earth had been on a gradual cooling trend, until the last 100 years, which has seen a big upturn of temperature." As one of the lead authors on the 2001 state-of-the-science report of the United Nations Intergovernmental Panel on Climate Change, Easterling helped to synthesize all the various competing (and sometimes contradictory) scientific reports on this warming trend. "When we talk about global warming, we're talking about an average warming across the Earth," he explained. Some computer models predict a hotter future than others; the U.N. panel chose one of the lower estimates: 1.4 to 5.8 degrees C of temperature rise by 2100. But, noted Easterling, "The Earth is only five degrees C warmer today than it was when we emerged out of the Pleistocene Ice Age."

These facts, he says, "bring the question into focus: If the warming continues as the computer models tell us it will, will this threaten our ability to feed the world's people?"

To find an answer, first forget about climate change. Even without global warming, can the Earth feed ten to 11 billion people?

That depends on four things, said Easterling, who is both a geographer and an agronomist and heads Penn State's Environmental Consortium: Can we increase the number of calories produced by the world's farmers? Can we keep food prices low? Can we do those two things without "trashing the planet"? And, finally, can we share that food worldwide? It's one thing to grow more, said Easterling. "It's quite another thing to ensure that food energy gets into the hands and mouths of the people who need it most."

As for the first point, raising the number of calories, "the challenge," Easterling said, "will be to raise the productivity of crops, since most of the Earth's better agricultural land is already being plowed. It comes down to whether technology will deliver ways to increase crop yields. The answer depends on if you're a technological optimist or a pessimist. If I was a betting person, I'd go with optimism. Our agricultural research community is one of the best there is," he continued. "It has repeatedly come through for us, and the literature continues to provide abundant evidence of new ways to increase yields. Without going into the new technology—biotechnology—and what it means, I think the potential to continue increasing the yield of crop plants is there, although not at the pace of the past half century."

Food prices, Easterling's second point, depend on supply and demand. Population increases the demand for food, but so, said Easterling, does income. "When people become wealthier, they aren't satisfied with eating coarse grains. They see beef as much superior, and if they have the money to spend on it, they'll buy it." According to the U.N. report, per capita income will rise along with population. Explained Easterling, "Wealth will become much more a function of information flying from one place to the next, and not so much of the items we produce." Yet after a point, this additional level of wealth will no longer affect food buying. "Experience shows that people quickly satisfy their food needs and turn to other non-food investments." Just as population growth is expected to taper off, the effect of growing wealth on food buying will lessen. "This indicates that supply will equal demand," Easterling says.

"By 2020, we're likely to see prices even cheaper than they are today, as new technologies decrease the real costs of production—unless the next problem is not dealt with, and that is the unpriced environmental cost of agriculture": the cost of pesticide and fertilizer runoff, erosion, salinization, and desertification. "If technology delivers strategies for reducing environmental costs," Easterling said, "farmers should be motivated to use those strategies to conserve resources."

"So will everyone have access to a good diet? In my opinion, here's where the optimism stops. It's not a serious problem to produce more food cheaply. But per capita production will not rise everywhere. And the places where it won't rise are the worse places possible." On the wide screen of the lecture hall Easterling projected a slide: a crowd of women, well-dressed, with patient faces, facing the camera, silent, expecting something. "These are Rwandans waiting for food," he said. "They waited in line all day, and it never came. The government didn't hand it out. Africa continues to see per capita food production decline. In many instances, stockpiled food is kept from the hungriest people by government inefficiencies, politics, and other social dysfunctions."

Will global warming exacerbate—or fix—any of these problems? Carbon dioxide is, of course, what plants breathe. Won't more carbon dioxide, a warmer climate, and the increase of rain expected to go along with it actually improve agriculture?

Yes, said Easterling—and no. "In the higher latitudes of the Earth, where most of the grain belts are today, the early stages of global warming, accompanied by rising carbon dioxide levels and an increase in rainfall, will probably cause our crop plants to increase their yields a little. So a little warmth is probably good—for a while.

"For our most high-value crop in America—corn—there will be no response or a small response in the positive direction for the first two degrees of warming. By the time you get to three or four degrees of warming, though, crops are experiencing severe physiological stress most of the time they are growing. It would be catastrophic to any farmer in America.

"When we get down into the tropics, this is where the story really goes south—both literally and figuratively. In the tropics, plants are already at their maximum temperature for photosynthesis. Any warming whatsoever will instantly be a challenge. In the tropics, with any warming at all, corn begins to suffer.

"So this is a bittersweet picture. It suggests that, at least in the northern latitudes, we might be able to get by for a while and do very well with climate change, but then the warming benefit disappears."

Ever the optimist, Easterling pointed out that new grain belts could arise in Siberia and central Canada. Farmers, those "intrinsically resourceful" people, will introduce new crops like triticale, a recent synthesis of rye and wheat. Japanese rice breeders have developed a strain that can continue to convert sunlight into food "at a point well above the temperature where a plant usually cuts off photosynthesis." Other crops are being bred to deal with the stress of 24-hour daylight in the new crop fields of the far north.

The cost of food should also be unaffected by the first two to three degrees of warming. "Again, for a while, we'll be okay," Easterling said. "But after a warming of two to three degrees, then the prices will begin to turn up. Decreases in food production in the tropics will be balanced by increases in the higher latitudes. If markets don't perform well, that will be problematic."

Then there's that question of "trashing the planet." "The environmental costs are again the wild card," Easterling said. "They could cause this house of cards I have built to fall down. If erosion is not dealt with, and other problems, we'll see farms simply become less productive. Moreover, we don't know what's going to happen to weeds over climate change. Carbon dioxide will at times favor the weed—and the weed will win. Honey mesquite, a pest in the Great Plains, does very well with an increase in carbon dioxide, but little bluestem"—what grazing cattle eat—"is not as responsive. We really haven't factored that into our thinking very well."

Even if the house of cards stays standing—even if new biotech crops, new agricultural techniques that create sustainable agro-ecosystems, and new, ever-more-clever farmers succeed, in spite of global warming, in producing enough calories to nourish ten billion bodies and minds—even then, we have to learn to share. "Under either scenario, with global warming or without, I don't think we will have dealt very effectively with distribution issues. We'll still end up with a lot of new people technically classified as malnourished," Easterling concluded. "The real problem has to do with political institutions. The political economy is the problem for food distribution."

William Easterling, Ph.D., is director of the Environmental Consortium at Penn State and professor of geography and agronomy, College of Earth and Mineral Sciences. He was a lead author on Climate Change 2001: Impacts, Adaptation, and Vulnerability, the report of the Intergovernmental Panel on Climate Change.

Last Updated May 01, 2002