Global warming increases ammonia emissions and reduces the efficacy of mitigation actions

Agricultural ammonia (NH 3 ) emissions adversely affect air quality, threatening ecosystems and human health. The extent to which global NH 3 emissions respond to a warmer climate and the effects of changing agricultural management practices remain poorly quantified. Here, we show that global warming drives NH 3 emission increases of 5-22% across plausible ranges of climate projections in 2091-2100, with > 10% regional increase in NH 3 emissions per °C warming. A package of six linked measures could reduce present global agricultural NH 3 emissions by 31% but only by 16-28% globally for contrasting climate scenarios (2091-2100), with up to 97% decrease in the effectiveness of measures at a continental scale. Our study underscores the need to consider temperature dependence when evaluating the efficacy of NH 3 emissions reduction policies under a changing climate, and highlights that achieving ambitious NH 3 emission abatement targets will require enhanced efforts to mitigate climate change.