Comprehensive quantification of global cropland ammonia emissions and potential abatement

Ammonia (NH3) emissions mostly from agriculture result in air pollution and degrade human health. However, a full picture of soil NH3 emissions and associated abatement in cropping systems are not well understood. Here we present a thorough analysis of cropland NH3 emissions, discuss mitigation potential and assess associated abatement costs. Global cropland NH3 emissions account for 26% of total soil nitrogen losses, and are estimated as 22.8-31.2 Tg N yr(-1) during 1996-2013 with the increase rate of 1.6% yr(-1). Our results also show that, with no increase in nitrogen fertilizer, climate change can contribute to an additional 10% increase in cropland NH3 emissions in 2100 compared to the 2010 baseline. Instead, our scenario analysis show, cropland NH3 emissions will decline by 26% from 2010 to 2100 given a 0.5% yr(-1) decrease in N fertilizer (with current technology and agricultural management level), considering the facts stronger control policies are expected to occur world wide including Western Europe, the United States of America and China. The most ambitious management (with all known mitigation practices) can reduce cropland NH3 emissions by up (71%, 17.6 Tg N yr(-1)) at an abatement cost of US$524 billion. Our findings indicate that cropland NH3 emissions can be mitigated through adoption of appropriate human management practices with considerable economic costs, providing a critical reference for the future NH3 abatement strategies. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Ammonia (NH3) emissions from agriculture contribute to air pollution and have negative effects on human health. This study provides a comprehensive analysis of NH3 emissions from croplands, examines the potential for mitigation, and assesses the associated costs. The results show that global cropland NH3 emissions account for 26% of total soil nitrogen losses, with an estimated range of 22.8-31.2 Tg N yr(-1) during 1996-2013. Climate change could lead to a 10% increase in cropland NH3 emissions by 2100 compared to the 2010 baseline, but stricter control policies are expected to reduce emissions by 26% from 2010 to 2100. The most ambitious management practices can achieve a 71% reduction in cropland NH3 emissions at a cost of US$524 billion.