A Quest for the Perfect Potato

Peru is considered to be one of the most vulnerable countries in the world to climate change. On the steep slopes of Chopcca, a community of 10,000 residents in the Andes, the rains come later, don't last as long and end more abruptly than they did only a few years ago. Frosts and hail hit earlier and more frequently. Fewer clouds drift by to moderate the extremes of temperature. Water shortages loom. In May, Mount Pastoruri, formerly a tourist attraction in the central state of Ancash, was removed from the list of snowcapped peaks because a third of its white cover has melted away. A 2002 study by the Tyndall Centre

for Climate Change Research in Britain found that the country's fragile mountain ecosystems, dependence on glaciers for water and extreme poverty make the job of adapting to the changes of global warming particularly difficult.

In the past few years, however, a funny thing happened on the way to catastrophe. Peruvian peasants have surprised the experts by coping with the warming. Small farmers in the Andean highlands have responded to changes in weather patterns by altering their planting season and varying their crops. Vulnerable mountain farmers are applying ancient strategies of risk diversification and a combination of homegrown experimentation and scientific know-how to adapt to the new weather patterns and their side effects.

It's difficult to overstate the challenge that these farmers face: a destructive synergy of climate change, overpopulation and land degradation runs the 8,000-kilometer stretch from Venezuela to Chile. As natural pasture is turned over to food crops, and population pressures decrease the amount of time fields lie fallow, virgin soils quickly grow depleted of nutrients and livestock go undernourished. "All the factors that create habitat degradation are made worse by climate change," says Stephan Halloy, director of the Andes biodiversity science unit for Conservation International.

The Andean farmers have felt the heat. Because of warming temperatures, crops now grow at higher altitudes than they did a few years ago. Farmers in Chopcca used to grow maize at 3,300 meters above sea level, but now plant at 3,600 meters. Pests have followed the crops to higher altitudes. In a remote corner of Cuzco province, native varieties of potatoes are being attacked by late blight, a fungus-like water mold. The Andean potato weevil, or potato white grub, eats potato leaves, and its larvae bore into the tubers underground. "We're in a war here with the Andean weevil," says Víctor Soto Ataypoma, mayor of Ccasapata, a village in Chopcca.

The campesinos have a natural weapon against climate change: the rich diversity of crop strains that flourish in the Andes's diverse system of habitats. Of the 34 known varieties of climate, Peru is home to 28 of them, and 70 percent of the country is covered by rain forest. Peru has 2,700 native varieties of potato and 35 types of corn, suitable to different climatic circumstances, including length of growing season, water and nutrient requirements, and pest resistance. Plant breeders and agronomists have stepped in to help Peru's farmers take advantage of this resource. In Chopcca, Yanapai, an agricultural NGO, has expanded the stock of native varieties of potato and tested organic methods for controlling pests. "Keeping alive a diversity of native varieties in a seed bank and complementing them with improved seeds should help the farmers adapt to climate change," says María Scurrah, a Cornell-trained plant breeder and coordinator of Yanapai.