Overestimated nitrogen loss from denitrification for natural terrestrial ecosystems in CMIP6 Earth System Models

Maoyuan Feng; Shushi Peng; Yilong Wang; Philippe Ciais; Daniel S Goll; Jinfeng Chang; Yunting Fang; Benjamin Z Houlton; Gang Liu; Yan Sun; Yi Xi

doi:10.1038/s41467-023-38803-z

Overestimated nitrogen loss from denitrification for natural terrestrial ecosystems in CMIP6 Earth System Models

Nat Commun. 2023 May 27;14(1):3065. doi: 10.1038/s41467-023-38803-z.

Authors

Maoyuan Feng^{1

2}, Shushi Peng^{3

4}, Yilong Wang⁵, Philippe Ciais^{6

7}, Daniel S Goll⁶, Jinfeng Chang⁸, Yunting Fang⁹, Benjamin Z Houlton¹⁰, Gang Liu^{1

2}, Yan Sun¹¹, Yi Xi^{1

6}

Affiliations

¹ Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, and Laboratory for Earth Surface Processes, Peking University, Beijing, China.
² Institute of Carbon Neutrality, Peking University, Beijing, China.
³ Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, and Laboratory for Earth Surface Processes, Peking University, Beijing, China. speng@pku.edu.cn.
⁴ Institute of Carbon Neutrality, Peking University, Beijing, China. speng@pku.edu.cn.
⁵ State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China.
⁶ Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France.
⁷ The Cyprus Institute 20 Konstantinou Kavafi Street, 2121, Nicosia, Cyprus.
⁸ College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
⁹ CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
¹⁰ Department of Ecology and Evolutionary Biology and Department of Global Development, CALS, Cornell University, Ithaca, NY, USA.
¹¹ College of Marine Life Sciences, Ocean University of China, Qingdao, China.

Abstract

Denitrification and leaching nitrogen (N) losses are poorly constrained in Earth System Models (ESMs). Here, we produce a global map of natural soil ¹⁵N abundance and quantify soil denitrification N loss for global natural ecosystems using an isotope-benchmarking method. We show an overestimation of denitrification by almost two times in the 13 ESMs of the Sixth Phase Coupled Model Intercomparison Project (CMIP6, 73 ± 31 Tg N yr^-1), compared with our estimate of 38 ± 11 Tg N yr^-1, which is rooted in isotope mass balance. Moreover, we find a negative correlation between the sensitivity of plant production to rising carbon dioxide (CO₂) concentration and denitrification in boreal regions, revealing that overestimated denitrification in ESMs would translate to an exaggeration of N limitation on the responses of plant growth to elevated CO₂. Our study highlights the need of improving the representation of the denitrification in ESMs and better assessing the effects of terrestrial ecosystems on CO₂ mitigation.

Abstract

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