Extreme Weather and Food Shocks

Sam Brewster

Sam Brewster

via The New York Times

Recent events highlight concerns about the risks to global food security posed by changing patterns of extreme weather affecting the world’s “breadbasket” regions such as the American Midwest, South America’s southern cone, the Black Sea and the Yangtze River valley. In 2012, the worst drought to hit the U.S. Midwest in half a century sent international maize and soybean prices to record levels. In 2011, wheat prices nearly doubled after an unprecedented heat wave devastated the Russian harvest. The global food price crisis of 2007-8 had its roots in a run of poor harvests in previous years.

Global food security largely depends on the production of a few “mega-crops” in the breadbasket regions: maize, wheat, rice and soybeans. On the whole, the system works well. International trade provides a global market for these specialized production centers, reducing the cost of food for billions of people by allowing agriculture to flourish where it can be most efficient. Trade also allows countries to meet unforeseen production shortfalls through imports, as Britain did in the summer of 2013 after floods spoiled the winter wheat harvest. But when extreme weather ruins the harvest in a breadbasket region, that’s not just a problem in the country affected, it’s a problem for all importing countries.

Of course the risk to the world’s food security doesn’t arise simply from bouts of bad weather. Weather’s impact can be compounded by the actions of governments and markets. Governments can make things much worse when, for example, they try to shore up domestic food supplies by banning or limiting agricultural exports, further pushing up international prices. The 2007-8 crisis saw over 30 governments impose export restrictions in a spiral of rising prices and collapsing market confidence; the 2011 wheat spike was amplified when Russia turned off exports.

Likewise it is becoming clear that severe weather shocks rippling through the food system can ignite wider instability. During the 2007-8 crisis, protests erupted in 61 countries and turned violent in 23. In the wake of the Russian heat wave, the price of bread was one of several grievances behind the Arab Spring. Once shocks to the food system spill over into other areas, they can cascade through economic and political systems with sometimes devastating consequences.

Amid these pressures, the global food system is coming under increasing strain, as highlighted in a recent report that we wrote in conjunction with other British and American experts for the U.K.-led Global Food Security program. Rising incomes and changing dietary preferences mean demand for food is growing faster than cereal yields. Water scarcity and soil depletion present challenges for agriculture, which faces sharper competition for resources from urbanization and energy production. A precarious supply-and-demand balance means the system is easily unbalanced.

The stability of the global food system faces risks from the increasingly frequent extreme weather that is being driven by climate change. For example, in the United States there were more than four times more weather events causing damage in excess of $1 billion (in 2011 prices) in 2007-11 than in 1980-85. Drought is a particularly powerful driver of global food shocks. Two episodes stand out: in 1988-9, when maize and soybean were seriously affected in the U.S. Midwest, and in 2002-3, when rice and wheat were hit in Eastern Europe and Western Asia.

Were these two events to happen in the same year — a multiple breadbasket failure — it would result in the loss of between 5 and 10 percent of the production of these major crops, more than enough to supply the basic calorie needs of the United States for a year. Until recently, such a calamity would have been expected every 100 to 200 years, but this number is shrinking rapidly due to climate change. An initial analysis of recent data suggests that the risk of a 1-in-100-year event during the second half of the last century is likely to increase to 1-in-30 years by 2040 — and perhaps even 1-in-15 years in the decades after 2050...

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Tim Benton is the academic director of the Global Security Program and a professor of population ecology at the University of Leeds. Rob Bailey is the research director for Energy, Environment and Resources at Chatham House.