Editor's Note: This is an extended version of the story that original ran in the June 2008 issue of Scientific American.

The recent surge in world food prices is already creating havoc in poor countries, and worse is to come. Food riots are spreading across Africa, though many are unreported in the international press. Moreover, the surge in wheat, maize and rice prices seen on commodities markets have not yet fully percolated into the shops and stalls of the poor countries or the budgets of relief organizations. Nor has the budget crunch facing relief organizations such as the World Food Program, which must buy food in world markets, been fully felt. The results could be calamitous unless offsetting policy actions are taken rapidly.

The facts are stark. A metric ton of wheat cost around $375 on the commodity exchanges in early 2006. In March 2008, it stood at over $900. Maize has gone from around $250 to $560 in the same period. Rice prices have also soared. The physical inventories of grain relative to demand are also down sharply in recent years.

Several factors are at play in the skyrocketing prices, reflecting both rising global demand and falling supplies of food grains. World incomes have been rising at around 5 percent annually in recent years, and 4 percent in per capita terms, leading to an increased global demand for food and for meat as a share of the diet. China’s economic growth, of course, has been double the world’s average. The rising demand for meat exacerbates the pressures on grain and oil-seed prices since several kilograms of animal feed are required to produce each kilogram of meat.

Feed grains have risen from around 30 percent of total global grain production to around 40 percent today. Land that would otherwise be planted to the main grains is shifting to soya bean and other oil seeds used for animal feed. It is forecast, for example, that U.S. farmers will cut maize plantings by 8 million acres, while raising soya-bean production by about the same amount. The grain supply side has also been disrupted by climate shocks, such as Australia’s massive droughts.

An even bigger blow has been the U.S. decision to subsidize conversion of maize into ethanol to blend with gasoline. This wrong-headed policy, pushed by an aggressive farm lobby, gives a 51-cent tax credit for each gallon of ethanol blended into gasoline. The 2005 Energy Policy Act mandates a minimum of 7.5 billion gallons of domestic renewable-fuel production, which will overwhelmingly be corn-based ethanol, by 2012. Consequently, up to a third of the U.S. mid-Western maize crop this year will be converted to ethanol, causing a cascade of price increases across the food chain. (Worse, use of ethanol instead of gasoline does little to reduce net carbon emissions once the energy-intensive full cycle of ethanol production-- including the energy-intensive fertilizer and transport needs --is taken into account.)

The food price increases are pummeling poor food-importing regions, with Africa by far the hardest hit. Several countries, such as Egypt, India and Vietnam, have cut off their rice exports in response to soaring prices at home, thereby exacerbating the effects on rice-importing countries. Even small changes in food prices can push the poor into hunger and destitution: as famously expounded by Nobel laureate Amartya Sen, some of the greatest famines in history were caused not by massive declines in grain production but rather by losses in the purchasing power of the poor.

At a time when hundreds of billions of dollars each year veer to war rather than peaceful development, and when media attention is riveted on the U.S. financial crises, it is hard to raise even a few billion dollars for desperately hungry people. Still, it is urgent to do so. At least four measures should be taken in response to soaring food prices.

First, the world should heed the call of U.N. Secretary-General Ban Ki-moon to fund a massive increase in Africa’s own food production. The needed technologies are available—high-yield seeds, fertilizer, small-scale irrigation—but the financing is not. The new African Green Revolution would initially subsidize peasant farmers’ access to high-yield technologies and thereby at least double grain yields. The funding would also help farm communities establish long-term micro-finance institutions to ensure continued access to improved agricultural inputs after the temporary subsidies are ended in a few years.

Second, the U.S. should end its misguided corn-to-ethanol subsidies. Farmers hardly need them given world demand for food and feed grains. There is certainly a case for re-doubling the scientific efforts to produce bio-fuels on lands which do not compete with food crops, for example from cellulosic ethanol, but this technology is still not ready for the market.

Third, the world should support longer-term research into higher agricultural production. Shockingly, the Bush administration is proposing to cut sharply the U.S. funding for tropical agriculture research in the Consultative Group for International Agriculture Research (CGIAR), just when that research is most urgently needed. This is an example of the Administration’s anti-scientific approach at its worst.

Finally, the world should follow through on the promised Climate Adaptation Fund announced last December in the Bali Climate Change conference, to help poor countries face the growing risks to food production from increasingly adverse climate conditions. Even as the world staunches the immediate crisis, there will be more wrenching dislocations as drought, heat stress, pest infestations and other climate-induced shocks occur increasingly often.

This story was originally printed with the title, "Surging Food Prices".