Threats for Global Food Supply of Increasing Surface Ozone - Spatial Assessment of Impacts and Adaptation Options

Surface ozone (O3) is a potent phytotoxic air pollutant and significantly reduces the productivity of important agricultural crops. Growing use of fossil fuel and changes in climate are increasing the global background surface ozone concentrations to levels that threaten regional and global food supply. We performed an integrated modeling study, considering biophysical and crop management factors, to identify the spatial pattern of ozone damage in lands suitable for crop cultivation and to assess the potential for adaptation for four key crops (wheat, maize, rice and soybean) under current and future air quality legislation. Results indicate that China, India and the United States are by far the most affected countries, bearing more than half of all global losses and threatened areas. Short-erm adaptive measures at farm level, such as shifting crop calendars (by changing sowing dates or using crop cultivars with different cycle lengths) can reduce ozone damage regionally but have only limited impact at the global level. Considering these limited benefits of adaptation, mitigation of O3 precursors remains the main option to secure regional and global food production.