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Farmers may get help in adapting to global warming

WASHINGTON—Facing the inevitability of global warming, agriculture experts are trying to help the world's farmers adapt to higher temperatures.

They're working to develop new varieties of crops that can better withstand heat, drought, flooding and other extreme weather. They also want to train farmers in poor countries in more efficient ways to use land and water.

"Climate change is already happening. It's not just in the future," said Cynthia Rosenzweig, the leader of the Climate Impacts Research Group at NASA's Goddard Institute for Space Studies in New York. "Warmer temperatures are already suppressing crop yields. Both more droughts and more floods are likely."

"We're going to have to adapt," agreed Martin Parry, the director of the Jackson Environment Institute at the University of East Anglia, England. "We're not going to be able to mitigate the problem away."

Rosenzweig and Parry were the principal speakers at a conference of international agricultural researchers this week in Washington. The meeting hall rang with gloomy predictions for 21st-century agriculture.

"Dry areas get drier; moist areas get moister," Parry said. "That's not what we like to see."

Almost all scientists agree that the world is getting warmer, but some disagree on the cause, the amount and what to do about it. Limiting the level of carbon dioxide, a "greenhouse gas" that traps the sun's heat, is costly and unpopular.

So far, global warming's effects are most notable in Earth's northern regions, where glaciers are shrinking and frozen tundra is melting. But poor people in tropical and subtropical countries in Africa, Asia and Latin America will be hit the hardest, the experts said.

"Anticipating and planning for climate change is imperative if farmers in poor countries are to avert forecast declines in yields of the world's most important food crops," said Louis Verchot, the lead scientist at the World Agroforestry Centre in Kenya.

For a while, warmer temperatures may increase crop yields in the United States, Canada and Russia, because carbon dioxide—abbreviated as CO2—makes plants grow faster.

"In early decades there is a potential for agricultural production to increase," Rosenzweig said. "CO2 is good for crops."

But the benefit will level off and decline, she said, because high heat interferes with photosynthesis, the process by which plants capture energy from the sun and turn it into food.

"The effects are very negative in the long term," she declared.

Robert Zeigler, the director of the International Rice Research Institute in the Philippines, said poor farmers needed "climate-ready crops and animals that can withstand environmental changes and extremes."

"The longer we wait, the more difficult situation we'll face," said Zeigler, who's used genetic techniques to create a variety of "waterproof rice" that can survive prolonged submersion during a flood. He said his variety, which is being introduced in flood-prone areas of India and Bangladesh, can last up to two weeks underwater, instead of only three days like other types of rice.

Some other examples of work under way to help farmers adapt to climate change:

_The International Maize and Wheat Improvement Center in Texcoco, Mexico, is using the techniques of molecular biology to find "hot spots" in corn DNA that could make plants more able to tolerate drought.

_The International Crops Research Institute for the Semi-Arid Tropics, based in Patancheru, India, is searching for stress-tolerance genes in sorghum and millet, drought-resistant crops, that it can transfer to less hardy plants such as corn and wheat.

_The International Water Management Institute, headquartered in Sri Lanka, has devised a simple and cheap "drip irrigation" system to deliver scarce water to crops. The $5 system consists of a raised bucket that sends water through pipes with holes that slowly release the water into the soil close to the plants, eliminating waste. As much as 70 percent of rainfall is lost to runoff and evaporation.


For more information, go to the Web site of the Consultative Group on International Agricultural Research at


(c) 2006, McClatchy-Tribune Information Services.

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