Facing a Threat to Farming and Food Supply
Monday, November 19, 2007
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.
Several recent analyses have concluded that the higher temperatures expected in coming years -- along with salt seepage into groundwater as sea levels rise and anticipated increases in flooding and droughts -- will disproportionately affect agriculture in the planet's lower latitudes, where most of the world's poor live.
India, on track to be the world's most populous country, could see a 40 percent decline in agricultural productivity by the 2080s as record heat waves bake its wheat-growing region, placing hundreds of millions of people at the brink of chronic hunger.
Africa -- where four out of five people make their living directly from the land -- could see agricultural downturns of 30 percent, forcing farmers to abandon traditional crops in favor of more heat-resistant and flood-tolerant ones such as rice. Worse, some African countries, including Senegal and war-torn Sudan, are on track to suffer what amounts to complete agricultural collapse, with productivity declines of more than 50 percent.
Even the emerging agricultural powerhouse of Latin America is poised to suffer reductions of 20 percent or more, which could return thriving exporters such as Brazil to the subsistence-oriented nations they were a few decades ago.
And those estimates do not count the effects of new plant pests and diseases, which are widely expected to come with climate change and could cancel out the positive "fertilizing" effects that higher carbon dioxide levels may offer some plants.
Scenarios like these -- and the recognition that even less-affected countries such as the United States will experience significant regional shifts in growing seasons, forcing new and sometimes disruptive changes in crop choices -- are providing the impetus for a new "green revolution." It is aimed not simply at boosting production, as the first revolution did with fertilizers, but at creating crops that can handle the heat, suck up the salt, not desiccate in a drought and even grow swimmingly while submerged.
The work involves conventional breeding of new varieties as well as genetic engineering to transfer specific traits from more resilient species. As part of those efforts, scientists are also busily preserving seeds from thousands of varieties of the 150 crops that make up most of the world's agricultural diversity, as well as wild relatives of those crops that may harbor useful but still unidentified genes.
"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.
But time is of the essence if a worldwide crisis in food security is to be avoided, said William R. Cline, a senior fellow at the Center for Global Development and the Peterson Institute for International Economics, Washington-based nonpartisan economic think tanks.