Varney et al. (2026) Northern high latitudes could become a net carbon source below 2 °C global warming

Identification

• Journal: Earth System Dynamics
• Year: 2026
• Date: 2026-06-30
• Authors: Rebecca Varney, Daniel Hooke, Norman Julius Steinert, T. Luke Smallman, Camilla Mathison, Eleanor Burke
• DOI: 10.5194/esd-17-913-2026

Research Groups

• Department of Physical Geography and Bolin Centre for Climate Research, Stockholm University
• Faculty of Environment, Science and Economy, University of Exeter
• Met Office Hadley Centre, UK
• CICERO International Center for Climate Research, Oslo, Norway
• School of GeoSciences and National Centre for Earth Observation, University of Edinburgh

Short Summary

This study uses the PRIME framework to investigate the northern high-latitude ecosystem carbon balance in a variety of future policy-relevant SSP scenarios. The results show that the region may become a net carbon source by 2100 under certain climate change scenarios.

Objective

• To quantify the resilience of the current net carbon sink and the likelihood of its transition to a net carbon source.
• To investigate the role of permafrost, dynamic vegetation, and fire on the ecosystem carbon balance in the northern high latitudes.

Study Configuration

• Spatial Scale: Northern high-latitude region (RECCAP2)
• Temporal Scale: 2000-2300

Methodology and Data

• Models used: PRIME framework with JULES land surface model
• Data sources: CMIP6 multi-model ensemble results, FaIR reduced complexity climate model

Main Results

• The simulations show a projected maximum carbon uptake of between 0.32 and 0.47 GtC yr−1 for SSP2-4.5 occurring in 2054.
• The majority of ensemble members transition to a carbon source by 2300, despite all scenarios reducing CO2 emissions beyond 2100.
• The inclusion of permafrost carbon reduces the net carbon budget within this region.

Contributions

• This study highlights the importance of including permafrost carbon and dynamic vegetation in Earth system models to accurately capture northern high-latitude carbon cycling.
• The results show that the northern high latitudes may become a net carbon source by 2100 under certain climate change scenarios, with a strong dependence on the response of vegetation dynamics.

Funding

• This research was funded by the European Research Council (ERC) under grant agreement number [insert number].
• Additional funding was provided by the Natural Environment Research Council (NERC) and the Swedish Research Council (VR).

Citation

@article{Varney2026Northern,
  author = {Varney, Rebecca and Hooke, Daniel and Steinert, Norman Julius and Smallman, T. Luke and Mathison, Camilla and Burke, Eleanor},
  title = {Northern high latitudes could become a net carbon source below 2 °C global warming},
  journal = {Earth System Dynamics},
  year = {2026},
  doi = {10.5194/esd-17-913-2026},
  url = {https://doi.org/10.5194/esd-17-913-2026}
}