Human-Generated Ozone Could Cut Global Crop Yields by 40% by 2100

An MIT study concludes that increasing levels of tropospheric ozone due to the growing use of fossil fuels under a business-as-usual scenario could cut global crop yields by nearly 40% worldwide by 2100, forcing a greater global allocation of land to agriculture.

Published in the journal Energy Policy, the study focuses on the affect of three environmental changes (increases in temperature, carbon dioxide and ozone) associated with human activity. The research shows while increases in temperature and in carbon dioxide may actually benefit vegetation on a global basis, especially in northern temperate regions, those benefits may be more than offset by the detrimental effects of increases in tropospheric ozone, notably on crops.
The economic cost of the damage will be moderated by changes in land use and by agricultural trade, with some regions more able to adapt than others. But the overall economic consequences will be considerable, with a global economic loss of 10-12% of the total value of crop production.

Even assuming that best-practice technology for controlling ozone is adopted worldwide, we see rapidly rising ozone concentrations in the coming decades. That result is both surprising and worrisome.
—John M. Reilly, associate director of the MIT Joint Program on the Science and Policy of Global Change

While others have looked at how changes in climate and in carbon dioxide concentrations may affect vegetation, Reilly and colleagues added to that mix changes in ozone. Moreover, they looked at the combined impact of all three environmental stressors at once, using the MIT Integrated Global Systems Model.

Reilly warns that the study’s climate projections may be overly optimistic. The researchers are now incorporating a more realistic climate simulation into their analysis.

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