Global ammonia emission could be halved with cost-effective measures

Excess ammonia (NH₃) emissions from human activities pose critical risks to global ecosystems and human health. Despite the urgent need for NH₃ emission controls, a comprehensive evaluation of the cost-effectiveness of mitigation strategies remains underdeveloped. In this study, we adopt a multi-model framework to assess the cost and impact of 32 mitigation measures across seven key sectors in 185 countries. Our results indicate that targeted implementation of these measures, particularly in the agricultural sector, could reduce global NH₃ emissions by 49% (36–57%). The estimated implementation cost of $279±69 billion outweighs the projected environmental, health, and resource benefits of $568±182 billion. China and India emerge as critical regions for prioritizing NH₃ mitigation, offering the highest societal returns, while Sub-Saharan Africa shows limited economic viability. Future scenario analysis reveals that sustainable policy pathways could reduce NH₃ emissions by 55% by 2050. Conversely, weak climate action and inadequate nitrogen regulations may result in a 19% increase in emissions, exacerbating environmental degradation and hindering progress toward sustainable development goals. Our findings underscore the urgent need for coordinated global efforts and region-specific policies to establish and achieve effective NH₃ mitigation targets.