A Process-Model Perspective on Recent Changes in the Carbon Cycle of North America

Guillermo Murray-Tortarolo, Benjamin Poulter, Rodrigo Vargas, Daniel Hayes, Anna M. Michalak, Christopher Williams, Lisamarie Windham-Myers, Jonathan A. Wang, Kimberly P. Wickland, David Butman, Hanqin Tian, Stephen Sitch, Pierre Friedlingstein, Mike O’Sullivan, Peter Briggs, Vivek Arora, Danica Lombardozzi, Atul K. Jain, Wenping Yuan, Roland SéférianJulia Nabel, Andy Wiltshire, Almut Arneth, Sebastian Lienert, Sönke Zaehle, Vladislav Bastrikov, Daniel Goll, Nicolas Vuichard, Anthony Walker, Etsushi Kato, Xu Yue, Zhen Zhang, Abhishek Chaterjee, Werner Kurz

Research output: Contribution to journalArticlepeer-review


Continental North America has been found to be a carbon (C) sink over recent decades by multiple studies employing a variety of estimation approaches. However, several key questions and uncertainties remain with these assessments. Here we used results from an ensemble of 19 state-of-the-art dynamic global vegetation models from the TRENDYv9 project to improve these estimates and study the drivers of its interannual variability. Our results show that North America has been a C sink with a magnitude of 0.37 ± 0.38 (mean and one standard deviation) PgC year−1 for the period 2000–2019 (0.31 and 0.44 PgC year−1 in each decade); split into 0.18 ± 0.12 PgC year−1 in Canada (0.15 and 0.20), 0.16 ± 0.17 in the United States (0.14 and 0.17), 0.02 ± 0.05 PgC year−1 in Mexico (0.02 and 0.02) and 0.01 ± 0.02 in Central America and the Caribbean (0.01 and 0.01). About 57% of the new C assimilated by terrestrial ecosystems is allocated into vegetation, 30% into soils, and 13% into litter. Losses of C due to fire account for 41% of the interannual variability of the mean net biome productivity for all North America in the model ensemble. Finally, we show that drought years (e.g., 2002) have the potential to shift the region to a small net C source in the simulations (−0.02 ± 0.46 PgC year−1). Our results highlight the importance of identifying the major drivers of the interannual variability of the continental-scale land C cycle along with the spatial distribution of local sink-source dynamics.

Original languageEnglish (US)
Article numbere2022JG006904
JournalJournal of Geophysical Research: Biogeosciences
Issue number9
StatePublished - Sep 2022

ASJC Scopus subject areas

  • Forestry
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Atmospheric Science
  • Palaeontology


Dive into the research topics of 'A Process-Model Perspective on Recent Changes in the Carbon Cycle of North America'. Together they form a unique fingerprint.

Cite this