Globally ubiquitous negative effects of nitrogen dioxide on crop growth.

Lobell, David B; Di Tommaso, Stefania; Burney, Jennifer A · Sci Adv · 2022

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Abstract

Nitrogen oxides (NO<sub>x</sub>) are among the most widely emitted pollutants in the world, yet their impacts on agriculture remain poorly known. NO<sub>x</sub> can directly damage crop cells and indirectly affect growth by promoting ozone (O<sub>3</sub>) and aerosol formation. We use satellite measures of both crop greenness and NO<sub>x</sub> during 2018-2020 to evaluate crop impacts for five major agricultural regions. We find consistent negative associations between NO<sub>2</sub> and greenness across regions and seasons. These effects are strongest in conditions where O<sub>3</sub> formation is NO<sub>x</sub> limited but remain significant even in locations where this pathway is muted, suggesting a role for direct NO<sub>x</sub> damage. Using simple counterfactuals and leveraging published relationships between greenness and growth, we estimate that reducing NO<sub>x</sub> levels to the current fifth percentile in each region would raise yields by ~25% for winter crops in China, ~15% for summer crops in China, and up to 10% in other regions.