Threat of Weather-Driven Food Shock Looms Large, Scientists Warn

What is a food shock? | Carla Schaffer /AAAS

A disappointing monsoon season shrinks wheat harvests in India and China in the spring. Months later, a severe drought wipes out soybean and maize in North America at the same time that a record-setting heat wave shrivels wheat in Europe.

This is "a plausible worst-case scenario" for how extreme weather can disrupt our global food system, said Tim Benton of the United Kingdom's Global Food Security Program in a 12 February panel discussion at the 2016 AAAS Annual Meeting. "We don't know for sure that this will happen, but these are the sorts of things that might happen."

Mounting evidence suggests that climate change can lead to more frequent and more severe extreme weather events, from intense storms and floods to heat waves and droughts. A "perfect storm" of these events occurring in multiple "breadbasket" or food-producing regions can have drastic global impacts, including malnutrition, spikes in food prices, and food riots.

The likelihood of a weather-driven food shock occurring in the next few decades is growing, warned Benton and colleagues, who are part of the U.K.-U.S. Taskforce on Extreme Weather and Global Food System Resilience. Their research suggests that the risk of a one-in 100 years food shock is likely to jump to one-in-30 years by 2040.

This finding could signal the dawn of a modern-day Dust Bowl, according to new research by Joshua Elliott from the University of Chicago. Elliott analyzed weather data from the 1930s Dust Bowl, one of the worst persistent droughts in recent U.S. history, to understand what a 21st-century Dust Bowl might look like.

"A drought like that, if it were to hit today, would be unprecedented," said Elliott. He found that a comparable shock in the present day would likely match or exceed food production losses from the 1930s. The worst drought year from the Dust Bowl, which was 1936, would be about 50% worse today than the most severe recent drought in the U.S. in 2012, resulting in harvest failures for maize and soy.

Conditions could rapidly worsen as climate change drives temperatures to rise. "As you go to higher temperature ranges, precipitation doesn't really matter as much because the crop is already under so much stress," said Elliott.

After mapping the geography of crop production, Kirsty Lewis, from the Met Office Hadley Center for Climate Science and Services in the United Kingdom, found that four major crops — maize, soy, wheat, and rice — are grown in narrow regions within only a few countries. "I was really, really surprised…[by] how concentrated food production is," said Lewis.

Matt Goode, Tim Benton, Kirsty Lewis, and Joshua Elliot at the 2016 AAAS Annual Meeting. | Ashley Gilleland / AAAS

The U.S. and China represent the major source of maize; the U.S. and Brazil are the principal producers of soy; wheat comes predominantly from Europe, India, and China; and India and China, along with other countries in South and Southeast Asia, are the main cultivators of rice.

These breadbasket regions present "vulnerability points" for food shocks, said Lewis, raising the question of whether crop production should be more diversified.

Despite its many benefits, the global food trade network can potentially amplify the risks of weather-driven food shocks, according to Benton. Food shocks are likely to hit hardest in poor and import-dependent countries, such as those in Sub-Saharan Africa.

Benton has been working with government leaders and policymakers around the world to address and manage food shock risks. "We ask, 'Are you prepared for the consequences?' And typically the answer is 'No,'" he said. "Governments are listening, but they aren't engaged as much as we would like them to be."

The researchers called for an international plan of action to make the food system more resilient, such as developing contingency plans and establishing early warning systems. Technology, better agricultural practices, and more sustainable use of resources can also help agriculture adapt to extreme weather.

"It is perfectly possible to mitigate a lot of these risks, but we have to plan for them," said Benton.