Tracing global NO emission mitigation strategies through trade networks.

Nitrous oxide (NO) is the third most potent greenhouse gas (GHG) and the most important ozone depleting substance. But how global NO emissions are connected through the interwoven trade network remains unclear. This paper attempts to specifically trace anthropogenic NO emissions via global trade networks using a multi-regional input-output model and a complex network model. Nearly one quarter of global NO emissions can be linked to products traded internationally in 2014. The top 20 economies contribute to about 70% of the total embodied NO emission flows. In terms of the trade embodied emissions classified by sources, cropland-, livestock-, chemistry-, and other industries-related embodied NO emissions account for 41.9%, 31.2%, 19.9%, and 7.0%, respectively. Clustering structure of the global NO flow network is revealed by the regional integration of 5 trading communities. Hub economies such as mainland China and the USA are collectors and distributors, and some emerging countries, such as Mexico, Brazil, India, and Russia, also exhibit dominance in different kinds of networks. This study selects the cattle sector to further verify that low production-side emission intensities and trade cooperation can lead to NO emission reduction. In view of the impact of trade networks on global NO emissions, achieving NO emission reduction calls for vigorous international cooperation.