Anthropogenic reactive nitrogen (Nr) has significantly increased since pre-industrial times, impacting climate through various atmospheric and land processes. This study reveals a net negative direct radiative forcing of -0.34 ± [-0.20, -0.50] W m⁻² in 2019 due to increased aerosol loading, reduced methane lifetime, and enhanced terrestrial carbon sequestration. These cooling effects outweigh warming from nitrous oxide and ozone. Future scenarios suggest this cooling may weaken due to reduced aerosol loading and increased methane lifetime, while N₂O-induced warming will likely increase. The study highlights the need to incorporate nitrogen deposition effects and ecosystem changes in future climate impact assessments.

Cheng Gong, Hanqin Tian, Hong Liao, Naiqing Pan, Shufen Pan, Akihiko Ito, Atul K. Jain, Sian Kou-Giesbrecht, Fortunat Joos, Qing Sun, Hao Shi, Nicolas Vuichard, Qing Zhu, Changhui Peng, Federico Maggi, Fiona H. M. Tang, Sönke Zaehle