Study: Climate change and air pollution will combine to curb food supplies

http://www.eurekalert.org/pub_releases/2014-07/miot-scc072414.php

PUBLIC RELEASE DATE: 27-Jul-2014

Contact: Kimberly Allen
Massachusetts Institute of Technology
Study: Climate change and air pollution will combine to curb food supplies
Ozone and higher temperatures can combine to reduce crop yields, but effects will vary by region

Many studies have shown the potential for global climate change to cut food supplies. But these studies have, for the most part, ignored the interactions between increasing temperature and air pollution — specifically ozone pollution, which is known to damage crops.

A new study involving researchers at MIT shows that these interactions can be quite significant, suggesting that policymakers need to take both warming and air pollution into account in addressing food security.

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While heat and ozone can each damage plants independently, the factors also interact. For example, warmer temperatures significantly increase production of ozone from the reactions, in sunlight, of volatile organic compounds and nitrogen oxides. Because of these interactions, the team found that 46 percent of damage to soybean crops that had previously been attributed to heat is actually caused by increased ozone.

Under some scenarios, the researchers found that pollution-control measures could make a major dent in the expected crop reductions following climate change. For example, while global food production was projected to fall by 15 percent under one scenario, larger emissions decreases projected in an alternate scenario reduce that drop to 9 percent.

Air pollution is even more decisive in shaping undernourishment in the developing world, the researchers found: Under the more pessimistic air-quality scenario, rates of malnourishment might increase from 18 to 27 percent by 2050 — about a 50 percent jump; under the more optimistic scenario, the rate would still increase, but that increase would almost be cut in half, they found.