Overestimated natural biological nitrogen fixation translates to an exaggerated CO2 fertilization effect in Earth system models

Proceedings of the National Academy of Sciences, Volume 122, Issue 48, December 2025. SignificanceEarth system models (ESMs) are used to project climate change, which depends in part on how much carbon plants take up. Nitrogen is an essential limiting nutrient to plant growth and carbon uptake, and it is increasingly incorporated into …