Climate change may be global in its sweep, but not all of globe's citizen will share equally in its woes. The truth is evident or more worrisome in its projected effects on agriculture. The higher temperatures expected in coming years – along with salt seepage into ground water as sea levels rise and anticipated increases in flooding and draughts – will disproportionately affect agriculture in the planet’s lower latitudes, where most of the world’s poor live.

World agriculture faces a serious decline within this century and 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 a so-called “business as usual” scenario in which greenhouse gas emissions continue to increase. Rich countries, which typically have lower average temperatures, will experience a much milder or even positive average affect, ranging from an 8 percent in productivity to a 6 percent decline.

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.

Africa, where four out of five people make their living directly from land, could experience agricultural downturns of 30 percent, forcing farmers to abandon traditional crops in favour of more heatresistant 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.China, further from the equator than most developing countries, could escape major damage on average, although its south central region would be in jeopardy. Similarly, in the United States, the projected reductions are 25 to 35 percent in the Southeast and the Southwestern plains but significant increases in the northern states.

Overall, agricultural productivity for the entire world is projected to decline from levels otherwise reached between 3 to 16 percent by 2080s as a consequence of global warming. The projections are the work ofWilliam Clime, a senior fellow at the Center for Global Development (CGD) and the Peterson Institute for International Economics.

The above 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.

Scientists are busy in preserving seeds from thousands of varieties of the 150 crops that makeup 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, have a wide pool of genetic diversity from which to develop crops with these unique traits.The work of developing adaptive plants has begun to pay off. Researchers have discovered ancient varieties of persian grasses, for example, that have a remarkable 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. Other research is building on the recent discovery of a gene that helps plants survive prolonged periods underwater.

“Crops grow in weather, not in climate,” said Robert Zeigler, director general of the International Rice Research Institute in the Philippines, 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.

Will better agricultural technology offset climate losses? With additional investments in technology and adaptation, the effect of climate change on actual agricultural production could be reduced. But because these inputs raise the cost of production, prices would also rise. Similarly, increased irrigation could help farmers cope with droughts and excessive heat but water shortages and high cost of irrigation systems mean it will not solve the problem, Cline said.

In conclusion, it can be stated that policy makers in rich countries and developing countries, are now beginning to understand that the impact of climate change will be profoundly unequal. The above projections are yet another indication that people who are concerned about global poverty also need to deeply concerned about global warming.