GLOBAL WARMING

Against the Grain

Supplies of rice, corn, and wheat--crops that yield half of the world's food calories--could shrink dramatically by 2050.

by Marilyn Werber Serafini

Sat. Jul 12, 2008


Energy & Environment Audio Slide Show


Watch an audio slide show of USDA's Lewis Ziska discussing the impact of climate change on the struggle between weeds and crops. Related Coverage
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Tall and sturdy in his demin shirt and jeans, Lewis Ziska appears the quintessential Iowa farmer. It's early June, and he plants a row of soybeans before pausing to admire the tender corn already poking through the soil in search of the warm sun. Then, Ziska deliberately sabotages one of his crops.

Right next to his soybeans, Ziska plants Canada thistle, one of the peskiest, most pervasive, unwanted weeds in the world. He knows that its giant, coarse stalks will quickly spread and overpower his soybeans, but that's exactly what he wants.

Ziska is not a farmer at all. He's a scientist at the Agriculture Department's research center in Beltsville, Md., and he's determined to battle the mounting threats that global warming poses to the world's food supplies. In this particular experiment, Ziska is studying the risks from weeds. And not just any weeds. Fueled by the increased carbon dioxide in the air, invasive plants have begun mutating into "superweeds" that grow bigger and faster and are harder to kill.

Already, the world's rice and wheat farmers are failing to keep pace with increases in demand, grain prices are on the rise, and gains in corn production have gone to ethanol instead of food. Some countries are restricting grain exports, and President Bush recently approved $200 million in emergency food aid for developing countries.

Factor in global warming, and Ziska begins to feel queasy. "We're approaching crisis point," he said. "Everyone thinks food comes from the local Safeway, but it doesn't."

By 2050, if climate change continues on its current trajectory, world supplies of rice, corn, and wheat--sometimes called the Big Three because together they provide half of the planet's food calories--could shrink dramatically. After 2050, wheat production alone could decline by 40 percent. And countries near the equator or at low elevations may feel the pinch sooner than that. Just as alarming, global warming could diminish the nutritional value of these essential crops.

Yet the money devoted to researching the problem--and potential responses--has dwindled, particularly in the United States. When Bush took office, 10 scientists in Ziska's department were studying the impact of global warming on food. Now only three are, because of administration-backed budget cuts.

USDA spokesman Keith Williams defends those cuts, contending that, although the Bush administration wants to close older facilities, it also wants to spend more on newer priorities, including some involving climate-change research. He pointed, for example, to the additional money that Bush seeks for studying water reuse--recapturing water to ease the impact of droughts--and for gene research that could help scientists identify and breed high-yield crops that can adapt to global warming.

According to USDA researchers, in addition to creating ferocious weeds, climate change threatens to raise temperatures so high in some places that certain crops can no longer thrive there, to reduce the water available for irrigation, to cause droughts and floods, to lessen seed production and plant pollination, and to strip some protein and other important nutrients from grains.

The development of high-yield varieties of corn, wheat, and rice during the "green revolution" of the 1960s and '70s reduced hunger around the world. Gone, it seemed, were the days when American children heard lectures about the starving children in China. "I can remember thinking, 'I hope all the starving kids like brussels sprouts,' " Ziska says. "Now, places like India and China, instead of being net importers of food, rather than living on the edge, they now have plenty of food and are actually exporting their food."

But the success of the green revolution lulled the world's leaders into complacency. Since that agricultural breakthrough, Earth's population has doubled. And, Ziska said, farmers have now realized most of the possible gains in yield. "So what was put off back in the '60s--those decisions that had to be made about where assistance was going to go, population control, and those sorts of things--those questions are now back with us again."

The USDA plant physiologist continued, "We've given ourselves a 30-year reprieve, but those questions haven't gone away. Instead of having 3 billion people in the world, we have 6 billion people." Because of climactic uncertainty, "you have a greater strain on the resources needed to grow these crops at the levels needed to support this population." For example, he said, water is "becoming scarce around the world.... And agriculture is the greatest user of fresh water in the world, so if you don't have that water, you cannot maintain the levels of productivity you need to support 6 billion people."

Turning Up the Heat

Outside of certain equatorial regions and flood-prone lowlands, climate change hasn't hurt food crops much so far. That's because one byproduct of global warming actually helps plants.

Vegetation thrives on carbon dioxide. The level of CO2 in the atmosphere has risen from 270 parts per million in pre-industrial days to 380 ppm today, according to Richard Sicher, a plant physiologist who works with Ziska. For now, the positive CO2 effects--crops grow faster and stronger--are neutralizing the effects of rising temperatures, according to David Lobell, a senior research scholar for Stanford University's Program on Food Security and the Environment.

But that balance won't hold forever, he warns. "When you look at the future, you have to understand that things won't necessarily keep progressing at the same pace. As temperature goes up, you can expect crops to continue to be negatively affected. As CO2 goes up, crops continue to be benefited by smaller amounts. There's a limit to how much benefit you get from higher CO2, but there's not a limit to how much damage you can get from higher temperatures."

By 2080, according to William Cline, a senior fellow at both the Peterson Institute for International Economics and the Center for Global Development, land temperatures will be an average of 5 degrees Celsius (9 degrees Fahrenheit) higher than they were in 1980. In farm areas, temperatures will rise 4.4 degrees Celsius by 2080, he predicts. But most experts identify 2050 as the tipping point, when rising carbon dioxide levels will no longer compensate for rising temperatures. By then, they forecast, average temperatures will be 2 degrees higher.

Lobell says that his recent research suggests "we're closer to the crossing point [when higher temperatures outweigh higher CO2 levels] than we thought. I think the crossing point is before 2 degrees." So far, average U.S. temperatures have risen just under 1 degree Celsius. Some parts of the world, though, are already more than 2 degrees warmer than in 1980, he said.

By 2030, some regions will be "pretty bad," Lobell says. "The biggest loss is in southern Africa, where corn [production] will be down by 30 percent. In India, wheat would be down 5 percent. Given how many people depend on those crops, this is important.... After [the tipping point], things are bad almost everywhere."

Some areas of the world, particularly near the equator and at low elevations, face potential agricultural losses of up to 38 percent by 2080, according to a study by Cline. "In the long list of potential problems from global warming, the risks to world agriculture stand out as among the most important," he wrote in a March article for Finance and Development, the International Monetary Fund's magazine.

Cline forecasts that the most critical crop losses will be in India (as high as 38 percent), Mexico (35 percent), South Africa (33 percent), and Ethiopia (31 percent). In the United States, crop production will actually increase 8 percent if farmers use carbon-rich fertilizer, he calculates, but decrease 6 percent if they don't. In any case, Cline says, the effects on U.S. farmland will vary tremendously by region, perhaps forcing the nation's breadbasket northward. In the Southeast and the Plains of the Southwest, crop production will drop 25 to 35 percent, he estimates.

Extraordinarily vigorous weeds, such as the Canada thistle that Ziska is growing, are another serious threat to cropland. Carbon dioxide energizes weeds even more than it does most grains and vegetables, creating intense competition on the farm. Ziska, whose soybeans and weeds are now duking it out at USDA's Agricultural Research Center in Beltsville, is piping in CO2 to simulate the environmental conditions that he expects by midcentury.

Ziska's soybeans have been genetically modified to withstand Roundup, the country's most common herbicide. But weed killers may not be a match for the problem. "We have shown in previous experiments that [Canada thistle] becomes harder to control with Roundup" because higher CO2 levels make some roots too deep for the poison to reach, Ziska said.

In addition to dealing with higher temperatures and more weeds, farmers can expect their irrigation problems to worsen as glaciers recede. "Mountain glaciers supply [water for] irrigation," Ziska notes. "When you lose that snow and ice, you [still] get spring rains, but then the water flows out to the ocean unless you catch it."

Another little-studied consequence of global warming affects the nutritional content of foodstuffs. Extra carbon dioxide makes plants grow larger but hampers their ability to produce protein. "When elevated CO2 stimulates photosynthesis, carbon dioxide from the air gets converted by the plant into sugar," said James Bunce, a plant physiologist at USDA's Crop Systems and Global Change Lab. "But nitrogen, which makes protein, has to come from the soil, so when you increase CO2, the plant gets a little bit unbalanced and it's making sugar faster than it can pull nitrogen from the soil and mix with it to make proteins. So what tends to happen at high CO2 is that the things that we want to eat from crops tend to become more carbohydrate and less protein." The protein content diminishes substantially in seed crops such as wheat and rice, "and that's kind of scary for people who depend on those two for a major part of their protein," Bunce said.

One positive CO2 note: It boosts cancer-fighting antioxidants in some foods, including strawberries, and boosts omega fatty acids in others.

Ryan Morris and Reuben Dalke/National Journal

Green Revolution 2.0

What the world needs, many scientists say, is another green revolution. Although the first focused on crossbreeding crops to produce higher-yielding varieties, a second would focus on developing plants that can thrive as the climate changes. Can researchers produce varieties better able to survive floods, or drought, or both? Can they engineer crops to break yield records by exploiting additional CO2 in the atmosphere?

In addition to his soybean-weed competition, Ziska is crossbreeding a common variety of edible rice with weedier strains. His goal is to produce a hardier edible variety. The International Rice Research Institute, a research organization funded primarily by various governments, has stockpiled 110,000 varieties of rice in a "doomsday" seed vault in Norway. "If you have a disease problem or want to adapt to climate change, you can go to the seed bank to find something to adapt to climate change," Ziska said. "Without that diversity, we're doomed."

As always, the challenge is money. In April, Nobel Peace Prize winner Norman Borlaug, the father of the first green revolution, sharply criticized the Bush administration in a New York Times column chastising the federal government for neglecting its role as a leader in agricultural science. "During the 1950s, I and other scientists, first in North America and later throughout the world, developed high-yielding wheat varieties that were resistant to stem rust and other diseases," he wrote. Between 1965 and 1985, world production of cereal grains--wheat, rice, corn, barley, and sorghum--increased from 1 billion to 1.8 billion metric tons--and prices dropped 40 percent.

But international support for wheat research has declined significantly, Borlaug continued, causing wheat production as a percentage of demand to drop to its lowest level since the 1940s, and prices to climb to their highest level in 25 years. Yet, he said, "the State Department is recommending ending American support for the international agricultural research centers that helped start the green revolution, including all money for wheat research." One of the 15 research centers, the International Rice Research Institute, got word in February that the U.S. Agency for International Development, a top donor, was planning to halt its contributions. The United States has been contributing up to $3 million of the rice institute's $40 million annual budget.

Since then, rice institute staffers say, U.S. officials have indicated a possible change of heart, but money remains a problem. "We would point directly to a downturn in support for public rice and agricultural research over the past decade as a key reason for our present problem in global food production in rice, wheat, and maize," said Duncan Macintosh, the institute's development director.

"Japan has been cutting support to our institute for the last six years, because of the economic situation in Japan. The Dutch, the Danes, [the] Netherlands all pulled back from agricultural research a couple of years ago," Macintosh said. At its peak, in the 1990s, the rice institute's budget was $60 million (in today's dollars). "We're down about one-third. Our staffing is now about 1,000, and that's down from about 2,500," he said.

Funding started to dry up because of food surpluses, according to Macintosh, and tighter budgets choked off research. Of the 110,000 rices in the doomsday vault, he said, "we only have good knowledge of 10 to 15 percent of those varieties. The other 80 percent we know nothing about. What is the tolerance to drought?"

Ziska and his fellow USDA scientists at the experimental station are also feeling the financial pinch. V.R. Reddy is the facility's research leader for the Crop Systems and Global Change Lab, part of USDA's Agricultural Research Service. The lab conducts studies aimed at improving the growth, yield, and quality of crops, and it focuses on plants' responses and adaptation to CO2, UV-visible irradiation, water, heat, air pollution, soil chemistry, and other factors.

Federal funds for the global-change program haven't increased in a decade, Reddy said. Fifty years ago, the Beltsville campus had 30,000 acres on which to experiment. Now it has 6,500, and about 40 percent of its buildings sit empty. The number of scientists has dropped from 450 to 260. Only three scientists now staff the lab.

Reddy's program used to have a scientist who studied how climate change affects the nutritional value of plants. Another had been examining the effect of ozone on plants. Now no one there is exploring either topic.

"We have a skeleton staff," Reddy said. "We could use five, six, 10 more scientists. Right now we can concentrate on only one to two species. This is a major issue, and we can't wait too long. It's the temperature that's the problem. It's a serious problem."

Climate Problems on the Hill

Ziska, Macintosh, and other researchers hope that the recent food shortages and spikes in food prices will make world leaders more willing to fund agricultural research. "There's new momentum. You can feel it," Macintosh said. But it takes a while to turn an ocean liner, he added.

To be sure, few understand the strain that global warming will put on croplands. "People see that glaciers are melting, but they don't translate it into [needing] more money for agriculture," Reddy said. Moreover, he said, most people don't feel any urgency about addressing a "crisis" that may be 40 years away.

Then there's the question of politics. In the United States, many Republican lawmakers increasingly agree with the vast majority of Democrats that global warming is a serious problem, but some continue to resist the idea. "The truth isn't Democratic or Republican," Ziska said. "We're looking for how climate change is going to impact agriculture, and we have to go where that takes us. It shouldn't be a question of whose policy we do or don't support. It should be a question of what the data show. And those data, in turn, should be used to guide policy makers in coming up with a sound and wise decision regarding agricultural management and food security."

Every year of Bush's presidency, Democratic members of Congress have fought for funds for the Beltsville research center. A trio of Maryland Democrats--Sens. Ben Cardin and Barbara Mikulski, and Rep. Steny Hoyer--take the lead these days in pushing for the center during the appropriations process.

"This administration is not interested" in researching climate change, Cardin told National Journal. "[Bush] has proposed significant reductions in the last several years. This administration has dug its head in the sand. They don't want to see the science, so the easiest way is to cut budgets."

Cardin planned to offer an amendment to broad climate-change legislation that would have been a first step toward getting all of the federal government's science programs to address global warming. He never got a chance, because Senate Republicans filibustered the main bill. Cardin sounds hopeful that his proposal will be part of any global-warming legislation that Congress passes next year.

"It will be clearly easier with [Barack] Obama [in the White House], but [presumptive Republican nominee John] McCain understands climate change," Cardin said.

Aggressive action to counter the effects of climate change on the world's staple crops is what is needed, says the Peterson Institute's Cline. Without urgent action, he fears a repeat of scenes of poverty and hunger like those John Steinbeck depicted in The Grapes of Wrath. "This historical experience [of the Depression-era Dust Bowl] and perhaps the present-day drought of biblical proportions in Australia should alert international policy makers to the risks to world agriculture of a hotter and drier world by late this century as a consequence of unarrested global warming," he wrote in Finance and Development.

Ziska believes that the only way to avoid the dire consequences that Cline warns of is for the U.S. government and its counterparts around the globe to make food a higher priority. "The most important science is growing food," Ziska says. "Civilization depends on it. It's foolish, shortsighted to ignore that. We've been complacent."

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