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Climate-induced food crisis seen by 2100
Jan. 10, 2009
Courtesy University of Washington
and World Science staff
Global warming will probably seriously
hamper crop yields in the world’s hotter zones by 2100, and could leave half
of all people short on food unless they adapt, a study has found. Send us a comment
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Compounding matters, the researchers said, the most at-risk areas, the
tropics and subtropics, include many of the poorest and fastest-growing
populations.
“You’re talking about hundreds of millions of additional people looking for food because they won’t be able to find it where they find it now,” said David Battisti, a University of Washington atmospheric scientist. He is lead author of the study in the Jan. 9 edition of
the research journal Science.
“The stresses on global food production from temperature alone are going to be huge, and that doesn’t take into account water supplies stressed by the higher temperatures.”
To cope, people will have to “take decades to develop new food crop varieties that can better withstand a warmer climate,” said collaborator Rosamond Naylor, director of the Program on Food Security and the Environment at Stanford University in California.
The study combined direct observations with data from 23 global climate models that contributed to Nobel prize-winning research in 2007 by the Intergovernmental Panel on Climate Change.
Battisti and Naylor concluded there is more than a 90 percent chance that by 2100 the lowest growing-season temperatures in the tropics and subtropics will be higher than any temperatures recorded there to date.
They used the data to re-assess historic instances of severe food insecurity, and concluded such cases are likely to happen more often. Those include severe episodes in France in 2003 and the Ukraine in 1972. In the case of the Ukraine, a near-record heat wave reduced wheat yields and contributed to disruptions in the global cereal market that lasted two years.
Back then, “people could always turn somewhere else to find food,” Naylor said. “But in the future there’s not going to be any place to turn unless we rethink our food supplies.”
The serious climate problems won’t be limited to the tropics, the scientists conclude. As an example, they cite record temperatures that struck Western Europe in June, July and August of 2003, killing an estimated 52,000 people. The summer-long heat wave in France and Italy cut wheat yields and fodder production by one-third. In France alone, temperatures were nearly 6.5 degrees Fahrenheit above the long-term mean, and the scientists say such temperatures could be normal for France by 2100.
In the tropics, the higher temperatures can be expected to cut yields of the primary food crops, maize and rice, by 20 to 40 percent, the researchers said. But rising temperatures also are likely to play havoc with soil moisture, cutting yields even further.
“We have to be rethinking agriculture systems as a whole, not only thinking about new varieties but also recognizing that many people will just move out of agriculture, and even move from the lands where they live now,” Naylor said.
Three billion people now live in the tropics and subtropics, and their number is expected to nearly double by the century’s end. The area stretches from the southern United States to northern Argentina and southern Brazil, from northern India and southern China to southern Australia and all of Africa.
The scientists said that many who now live in these areas subsist on less than $2 a day and depend largely on agriculture
to get by.
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Global warming will probably seriously alter crop yields in the tropics and subtropics by 2100, and could leave half the world’s population hungry unless people adapt, a study suggests. To compound matters, the population of this equatorial belt – from about 35 degrees north latitude to 35 degrees south latitude – is among the poorest on Earth and is growing faster than anywhere else. “The stresses on global food production from temperature alone are going to be huge, and that doesn’t take into account water supplies stressed by the higher temperatures,” said David Battisti, a University of Washington atmospheric sciences professor. He is lead author of the study in the Jan. 9 edition of Science. To cope, people will have to “take decades to develop new food crop varieties that can better withstand a warmer climate,” said collaborator Rosamond Naylor, director of the Program on Food Security and the Environment at Stanford University in California. The study combined direct observations with data from 23 global climate models that contributed to Nobel prize-winning research in 2007 by the Intergovernmental Panel on Climate Change. Battisti and Naylor concluded there is greater than a 90 percent probability that by 2100 the lowest growing-season temperatures in the tropics and subtropics will be higher than any temperatures recorded there to date. They used the data as a filter to view historic instances of severe food insecurity, and concluded such cases are likely to happen more often. Those include severe episodes in France in 2003 and the Ukraine in 1972. In the case of the Ukraine, a near-record heat wave reduced wheat yields and contributed to disruptions in the global cereal market that lasted two years. “I think what startled me the most is that when we looked at our historic examples there were ways to address the problem within a given year. People could always turn somewhere else to find food,” Naylor said. “But in the future there’s not going to be any place to turn unless we rethink our food supplies.” The serious climate problems won’t be limited to the tropics, the scientists conclude. As an example, they cite record temperatures that struck Western Europe in June, July and August of 2003, killing an estimated 52,000 people. The summer-long heat wave in France and Italy cut wheat yields and fodder production by one-third. In France alone, temperatures were nearly 6.5 degrees Fahrenheit above the long-term mean, and the scientists say such temperatures could be normal for France by 2100. In the tropics, the higher temperatures can be expected to cut yields of the primary food crops, maize and rice, by 20 to 40 percent, the researchers said. But rising temperatures also are likely to play havoc with soil moisture, cutting yields even further. “We have to be rethinking agriculture systems as a whole, not only thinking about new varieties but also recognizing that many people will just move out of agriculture, and even move from the lands where they live now,” Naylor said. Three billion people now live in the tropics and subtropics, and their number is expected to nearly double by the century’s end. The area stretches from the southern United States to northern Argentina and southern Brazil, from northern India and southern China to southern Australia and all of Africa. The scientists said that many who now live in these areas subsist on less than $2 a day and depend largely on agriculture for their livelihoods. “You are talking about hundreds of millions of additional people looking for food because they won’t be able to find it where they find it now,” Battisti said.