Impacts of Ozone on Agricultural Yields
Research team: Denise Mauzerall, Shiri Avnery (doctoral student), Xiaoping Wang (doctoral student) and collaborators
While extensive research on the impacts of ozone on agriculture has been conducted in the United States in the 1980s and in Europe in the 1990s, little research was focused on agriculture in Asia [Mauzerall and Wang, 2001]. Early research in my group helped fill that gap. We used a sophisticated atmospheric chemistry transport model (MOZART-2) to simulate ozone concentrations in 1990 and 2020 over Asia, and available concentration-response functions to characterize yield reductions due to ozone exposure. Our estimates show that due to ozone concentrations in 1990, China, Japan and South Korea lost 1–9% of their yield of wheat, rice and corn and 23–27% of their yield of soybeans. In 2020 we project grain loss due to increased levels of ozone pollution to be 2–16% for wheat, rice and corn and 28–35% for soybeans [Wang and Mauzerall, 2004]. Although we used the best tools available, our estimate has uncertainties associated with the accuracy of our emission inventory for 1990 and projected for 2020, with ozone concentrations simulated by MOZART-2, and with the application of concentration-response relationships for non-Asian crop cultivars to East Asia. Our results still signify, however, that East Asia, a region that produces over 20% of the world’s grain, is potentially on the cusp of major reductions in agricultural yields due to projected increases in surface ozone concentrations.
The substantial yield reductions reported in the paper described above catalyzed field research in China, funded by the Japanese government, to better characterize yield reductions in Asian crop cultivars resulting from present and projected elevated ozone concentrations. As an adviser to this project I learned that recent field results are indicating that Asian cultivars are at least as sensitive as those grown in the US and Europe.
My group has expanded work on the adverse impacts of ozone on agricultural yields in East Asia to examine the impact of surface ozone on global crop yield reductions in year 2000 and 2030 including crop production losses, economic damage and implications for world hunger [Avnery et al., 2010a, 2010b]. Our results indicate that year 2000 O3-induced global yield reductions ranged from 9-14% for soybean, 4-15% for wheat, and 2 - 6% for maize, depending on the metric used. Global crop production losses totaled 80-120 million metric tons, worth $11-18 billion annually (USD2000). We use optimistic and pessimistic scenarios of O3 precursor emissions in 2030 and calculate higher relative yield losses in 2030 under both scenarios with global losses of soybeans, wheat and corn ranging from 15-19%, 5-26% and 5-9% respectively. Although we do not factor in the larger crop production necessary to feed a global population 1-2 billion people larger in 2030 than today, based on 2000 crop production and simulated 2030 O3 concentrations we estimate total 2030 global agricultural losses to be worth $17-35 billion USD2000. Even under the most optimistic scenario of future ozone precursor emissions, O3 pollution poses a growing threat to global food security. O3 mitigation thus appears to be a valuable means to increase food availability for a rapidly rising global population without the increase in environmental degradation that would result from bringing additional land under cultivation or increasing fertilizer or pesticide application.
Publications
Avnery, S, DL Mauzerall, J Liu, LW Horowitz. Global Crop Yield Reductions due to Surface Ozone Exposure: 1. Year 2000 Crop Production Losses, Economic Damage, and Implications for World Hunger, Atmospheric Environment, submitted 2010.
Avnery, S, DL Mauzerall, J Liu, LW Horowitz. Global Crop Yield Reductions due to Surface Ozone Exposure: 2. Year 2030 Potential Crop Production Losses, Economic Damage, and Implications for World Hunger under Two Scenarios of O3 pollution, Atmospheric Environment, submitted 2010.
Mauzerall, D. L. and Wang, X., “Protecting Agricultural Crops from the Effects of Tropospheric Ozone Exposure: Reconciling Science and Standard Setting in the United States, Europe and Asia,” Annual Review of Energy and the Environment, 26, pp. 237-268, 2001.
Wang, X. and Mauzerall, D. L., “Characterizing Distributions of Surface Ozone and its Impact on Grain Production in China, Japan and South Korea: 1990 and 2020,” Atmospheric Environment, 38, pp. 4383-4402, 2004.