The report was prepared for negotiators currently trying to reach a global deal to fight climate change at the latest round of UN talks in Bangkok. It used climate models prepared by the National Center for Atmospheric Research in Colorado and the Commonwealth Scientific and Industrial Research Organization in Australia to arrive at estimates of how changes in growing seasons and rainfall patterns would affect farming in the developing world and elsewhere.
Without an ambitious injection of funds and new technology, wheat yields could plunge by more than 30 percent in developing countries, setting off a catastrophic rise in prices. Wheat prices, with unmitigated climate change, could rise by between 170 percent and 194 percent by the middle of this century, the report said.
Rice prices are projected to rise by 121 percent — and almost all of the increase will have to be passed on to the consumer, Nelson said.
The report did not take into account all the expected impacts of climate change — such as the loss of farmland because of rising sea levels, a rise in the number of insects and in plant disease, or changes in glacial melt. All these factors could increase the damage of climate change to agriculture.
Others who have examined the effects of climate change on agriculture have warned of the potential for conflict. In a new book, Plan B 4.0: Mobilising to Save Civilisation, published on Wednesday, Lester Brown, founder of the Earth Policy Institute, warns that sharp declines in world harvests because of climate change could threaten the world order.
“I am convinced that food is indeed the weak link,” he said.
Brown saw Asia as the epicenter of the crisis, with the latest science warning of a sea level rise of up to 6 feet (1.83m) by 2100. With even a 3-feet rise, Bangladesh could lose half of its rice land to rising seas; Vietnam, the world’s second-largest producer of rice, could also see much of the Mekong Delta under water.
Wheat and rice production would also fall because of acute water shortages, caused by past over-pumping and the melting of the Himalayan glaciers, which currently store water that supplies the region’s main rivers: the Indus, Ganges, and Yangtse.
“The potential loss of these mountain glaciers in the Himalayas is the most massive projected threat to food security ever seen,” Brown said.
RSS