Food Security Wanes as World Warms

By Janet Raloff, Science News

Since summer, signs of severe food insecurity—droughts, food riots, five- to tenfold increases in produce costs—have erupted around the globe. Several new reports now argue that regionally catastrophic crop failures—largely due to heat stress—are signals that global warming may have begun outpacing the ability of farmers to adapt.

Some one billion people already suffer serious malnutrition. That number could mushroom, the new reports argue, if governments big and small don’t begin heeding warning signs like spikes in the price of food staples.

Severe summer droughts in Russia, Ukraine and Kazakhstan ravaged 2010 cereal yields. When Russia, the fourth largest wheat exporter, imposed an export ban in August, international markets responded with price spikes. Having sold around 17 million metric tons on world markets in 2009, Russia’s 2010 wheat exports are expected to fall closer to 4 million metric tons, according to a November Food Outlook report by the United Nations Food and Agricultural Organization, or FAO. (Russia’s export ban is slated to remain in effect until next July.)

Overall, FAO reports, food imports by the world’s poorest nations are expected to cost 11 percent more in 2010 than a year earlier—and 20 percent more for some low-income food-importing countries. FAO predicts the total cost of 2010 food imports will be roughly $1 trillion—a near-record level. Contributing to the problem is a 2 percent drop in global cereal yields; earlier this year 2010 cereal production had been expected to post a 1 percent gain.

Food prices offer a good proxy for agriculture’s health, notes Gerald Nelson, an economist with the International Food Policy Research Institute in Washington, D.C. Rising prices signal increasing resource scarcity, he explains, which can be triggered by expanding populations, growing incomes (because people can afford more and better food) and declining crop yields.

Recent food-price shocks and yield shortfalls initially surprised analysts, note IFPRI’s Derek Headey and Shenggen Fan in a November 18 report. Government officials had been lulled into complacency by decades of falling food costs. But prices bottomed out around 2000 and have since begun climbing in response to commodities speculation and a string of poor harvests, the pair notes.

Nelson and his colleagues have now used computer models to get some grasp on how crop yields and prices might respond, several decades out, to Earth’s continuing low-grade fever.

The team considered three scenarios of income and population growth that might reasonably be expected to occur between 2020 and 2050. Then they applied four “plausible” climate scenarios with warmer temperatures and anywhere from slightly to substantially wetter weather. They also included an “implausible fifth scenario of perfect mitigation (a continuation of today’s climate into the future).”

The resulting 15 scenarios all indicated that in contrast to the 20th century, when food prices fell, the 21st century would see prices rise. Probably by a lot.

Even with today’s climate, food prices would rise over the next 40 years in response to pressures from growing populations and incomes. Rice prices, for instance, would increase roughly 11 to 55 percent. Throw in additional warming and prices can rise substantially more—a minimum of 31 percent for rice and perhaps a doubling for corn.

The analyses clearly point to “climate change as a threat-multiplier,” concludes Nelson. His team unveiled its findings December 1 in a report prepared for release at the United Nations Framework Convention on Climate Change meeting in Cancun, Mexico.

Lighter wallets are hardly the most dire fallout of rising food costs. An analysis that Nelson’s group issued last year projected that food affordability by 2050 will likely trigger a decline in intake throughout the developing world—with people downing fewer calories than was typical in 2000. This could hike child malnutrition rates 20 percent above what would occur in the absence of climate change, Nelson’s group concluded.