Cost-effective mitigation of nitrogen pollution from global croplands

Cropland is a main source of global nitrogen pollution. Mitigating nitrogen pollution from global croplands is challenging due to non-point-source characteristics and constraints such as limited financial resources and farmer knowledge. Synthesizing 1,521 field observations worldwide, the study identifies 11 key measures that can reduce nitrogen losses to air and water by 30–70%, while increasing crop yield by 10–30% and nitrogen use efficiency (NUE) by 10–80%. Adoption of this package on global croplands (base year 2015) would enable production of 17 ± 3 Tg more crop nitrogen (20% increase) with 22 ± 4 Tg less nitrogen fertilizer used (21% reduction) and 26 ± 5 Tg less nitrogen pollution (32% reduction). The global societal benefit is estimated at 476 ± 123 billion USD across food supply, human health, ecosystems and climate, with net mitigation costs of 19 ± 5 billion USD, partly offset by 15 ± 4 billion USD fertilizer savings (44% of gross cost). To support implementation, innovative policies such as a nitrogen credit system (NCS) are proposed to select and incentivize adoption of measures.

Baojing Gu, Xiuming Zhang, Shu Kee Lam, Yingliang Yu, Hans J. M. van Grinsven, Shaohui Zhang, Xiaoxi Wang, Benjamin Leon Bodirsky, Sitong Wang, Jiakun Duan, Chenchen Ren, Lex Bouwman, Wim de Vries, Jianming Xu, Mark A. Sutton, Deli Chen