This CGD brief, based on Global Warming and Agriculture: Impact Estimates by Country, by senior fellow William Cline, explores the implications of global warming for world agriculture, with special attention to China, India, Brazil, and the poor countries of the tropical belt in Africa and Latin America. The brief shows that the long-term effects on world agriculture productivity will be substantially negative: developing countries, many of which have average temperatures that are already near or above crop tolerance levels, are predicted to suffer an average 10 to 25 percent decline in agricultural productivity by the 2080s, assuming the so-called "business as usual" scenario in which greenhouse gas emissions continue to increase.
Individual developing countries face even larger declines. India, for example, could see a drop of 30 to 40 percent. Some smaller countries suffer what could only be described as an agricultural productivity collapse. Sudan, already wracked by civil war fueled in part by failing rains, is projected to suffer as much as a 56 percent reduction in agricultural production potential; Senegal, a 52 percent fall. China, further from the equator than most developing countries, could escape major damage on average, although its south central region would be in jeopardy. The picture is similar in the United States, with projected reductions of 25 to 35 percent in the southeast and the southwestern plains increased agricultural productivity in the northern states.