Monday, November 19, 2007

Facing a threat to farming and food supply

Washington Post, by Rick Weiss: Climate change may be global in its sweep, but not all of the globe's citizens will share equally in its woes. And nowhere is that truth more evident, or more worrisome, than in its projected effects on agriculture.

…"For agriculture to adapt, crops must adapt," said Ren Wang, director of the Consultative Group on International Agricultural Research, a network of agricultural research centers. "It's important that we have a wide pool of genetic diversity from which to develop crops with these unique traits."

At the same time, scientists are finding that agriculture and related land uses, which today account for about one-third of all greenhouse gases emitted by human activities, can be conducted in much more climate-friendly ways.

…The work of developing adaptive plants has begun to pay off. Researchers have discovered ancient varieties of Persian grasses, for example, that have an incredible tolerance for salt water. The scientists are breeding the grasses with commercial varieties of wheat and have found they are growing well in Australia's increasingly salty soils.

…"Crops grow in weather, not in climate," Zeigler said, meaning they must be able to survive not only the anticipated average rises in temperature but also the day-to-day extremes that come with climate change.

…To the extent that plants cannot adapt to change, farmers will have to. In Uganda, where coffee is an important cash crop but where temperature increases are expected to devastate the plants, researchers are hoping that by planting shade trees, growers can preserve the industry while perhaps even increasing biodiversity. In other parts of Africa, farmers are being taught to add fruit trees to their subsistence farms. The trees can survive droughts and waterlogging better than crops planted annually, and so can serve as an economic bridge across hard times. Farmers in developed countries must also prepare, experts say.

…By changing their practices, and not just their crops, farmers can also temper the buildup of greenhouse gases. New technologies that measure soil nutrient levels are allowing farmers to add only as much fertilizer as is really needed -- important because the excess nitrogen in those chemicals gets converted in the soil into nitrous oxide, which has 300 times the greenhouse activity of carbon dioxide.

Studies also show that by plowing or tilling less frequently -- planting seeds in the stubble of a previous crop, for example -- farmers can significantly reduce evaporation in dry areas and also cut the amount of carbon dioxide released from the soil (and from the exhaust of their tractors, if they have them). Crops grown this way also trap carbon more effectively, becoming part of the solution instead of adding to the problem.

For the truly pessimistic, there is always the "doomsday vault," a seed bank being constructed in a Norwegian mountainside that nations around the world are stocking with every kind of seed imaginable.

After all, you never know what kind of plant trait is going to save humanity if the climate makes an unexpected turn, said Cary Fowler, executive director of the Global Crop Diversity Trust, which is leading the effort and who has boasted that the vault will be protected in part by the region's polar bears. That is assuming, of course, that rising temperatures or the newly arrived wheat farmers will not have driven them away.

No comments: