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Better crop rotation and irrigation can help protect fields from exhaustion and erosion. Old-fashioned cross-breeding can yield plant strains that are heartier and more pest-resistant. But in a world that needs action fast, genetic engineering must still have a role--provided it produces suitable crops. Increasingly, those crops are being created not just by giant biotech firms but also by home-grown groups that know best what local consumers need.
The National Agricultural Research Organization of Uganda has developed corn varieties that are more resistant to disease and thrive in soil that is poor in nitrogen. Agronomists in Kenya are developing a sweet potato that wards off viruses. Also in the works are drought-tolerant, disease-defeating and vitamin-fortified forms of such crops as sorghum and cassava--hardly staples in the West, but essentials elsewhere in the world. The key, explains economist Jeffrey Sachs, head of Columbia University's Earth Institute, is not to dictate food policy from the West but to help the developing world build its own biotech infrastructure so it can produce the things it needs the most. "We can't presume that our technologies will bail out poor people in Malawi," he says. "They need their own improved varieties of sorghum and millet, not our genetically improved varieties of wheat and soybeans."
--WATER: For a world that is 70% water, things are drying up fast. Only 2.5% of water is fresh, and only a fraction of that is accessible. Meanwhile, each of us requires about 50 quarts per day for drinking, bathing, cooking and other basic needs. At present, 1.1 billion people lack access to clean drinking water and more than 2.4 billion lack adequate sanitation. "Unless we take swift and decisive action," says U.N. Secretary-General Kofi Annan, "by 2025, two-thirds of the world's population may be living in countries that face serious water shortages."
The answer is to get smart about how we use water. Agriculture accounts for about two-thirds of the fresh water consumed. A report prepared for the summit thus endorses the "more crop per drop" approach, which calls for more efficient irrigation techniques, planting of drought- and salt-tolerant crop varieties that require less water and better monitoring of growing conditions, such as soil humidity levels. Improving water-delivery systems would also help, reducing the amount that is lost en route to the people who use it.
One program winning quick support is dubbed WASH--for Water, Sanitation and Hygiene for All--a global effort that aims to provide water services and hygiene training to everyone who lacks them by 2015. Already, the U.N., 28 governments and many nongovernmental organizations (ngos) have signed on.
--ENERGY AND CLIMATE: In the U.S., people think of rural electrification as a long-ago legacy of the New Deal. In many parts of the world, it hasn't even happened yet. About 2.5 billion people have no access to modern energy services, and the power demands of developing economies are expected to grow 2.5% per year. But if those demands are met by burning fossil fuels such as oil, coal and gas, more and more carbon dioxide and other greenhouse gases will hit the atmosphere. That, scientists tell us, will promote global warming, which could lead to rising seas, fiercer storms, severe droughts and other climatic disruptions.