Intense Warming Will Significantly Increase Cropland Ammonia Volatilization Threatening Food Security and Ecosystem Health

Cropland ammonia volatilization (V-NH3,V-AG) is a major pathway of agricultural nitrogen loss. It remains unclear, however, how climate warming and human intervention (e.g., agricultural management) will affect V-NH3,V-AG. Here, we use a fully coupled agroecosystem/chemical transport model and multiple climate projections to quantify the changes in climate-induced V-NH3,V-AG over the US. We show that climate change under an intensely warming scenario will increase V-NH3,V-AG by 81% (95% confidence interval, 69%-92%) from 2010 to 2100. The increase in V-NH3,V-AG will cause a 10% loss of nitrogen applied, decrease crop yields by 540 Gg-N year(-1), increase atmospheric burden of ammonia/ammonium by 18%, and increase ammonia/ammonium deposition to sensitive ecosystems by 14%. We have found that combining climate-adaptive agricultural practices with feasible mitigation measures can fully offset the warming-induced increase in V-NH3,V-AG, saving 13% of applied nitrogen, increasing yields by 735 Gg-N year(-1), and providing net benefits for air quality and ecosystem health.