Impact of air-ice CO2 fluxes on polar ocean carbon budgets from a bipolar data compilation
In ocean carbon budget assessments, sea ice is still treated as an impermeable barrier, rather than a dynamic interface mediating CO₂ exchange between ocean and atmosphere. We compiled more than 6000 chamber-based air–ice CO₂ flux measurements from the Arctic and Southern Oceans between 2003 and 2021, spanning diverse ice, snow, and seasonal conditions. These data show that sea ice releases CO₂ in winter and absorbs it in summer, with summer uptake offsetting winter emissions. On an annual basis, sea ice represents a small net CO₂ source of +4 Tg C yr⁻¹ in the Arctic and +2 Tg C yr⁻¹ in the Southern Ocean, challenging earlier views of a major sink. Although these fluxes are negligible at basin scales relative to open-ocean uptake, sea ice exchanges gases even in cold winter conditions, with implications for small-scale processes and other trace gases, underscoring the need for sustained, process-resolving observations. A bipolar compilation of air-sea ice CO2 fluxes shows that sea ice emits CO2 in winter and absorbs it in summer. Annually, the sea ice represents a small net source of 2 to 4 Tg C per year for each polar ocean, negligible relative to total open-ocean carbon uptake.
Authors
- Victoria Dutch (ORCID: https://orcid.org/0000-0002-4482-2853)
- Sebastien Moreau (ORCID: https://orcid.org/0000-0001-9446-812X)
- Bruno Delille (ORCID: https://orcid.org/0000-0003-0502-8101)
- Laique M. Djeutchouang (ORCID: https://orcid.org/0000-0001-7884-4586)
- Odile Crabeck (ORCID: https://orcid.org/0000-0003-1882-9303)
- G. T. Else Brent
- Lisa A. Miller (ORCID: https://orcid.org/0000-0001-9726-3744)
- Daiki Nomura (ORCID: https://orcid.org/0000-0003-3047-4023)
Institutions
- University of East Anglia (GB)
- Fisheries and Oceans Canada (CA)
- Université Libre de Bruxelles (BE)
- University of Liège (BE)
- University of Calgary (CA)
- Hokkaido University (JP)
- Stellenbosch University (ZA)
- University of Oxford (GB)
- Southern Ocean Medical Center (US)
- University of California, Davis (US)
- Norwegian Polar Institute (NO)
Publication Details
- Journal
- Nature Communications
- Published
- 2026-05-29
- DOI
- https://doi.org/10.1038/s41467-026-73737-2
- Primary Topic
- Atmospheric and Environmental Gas Dynamics
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- UK Research and Innovation
- Biodiversa+
- Scientific Committee on Antarctic Research
- European Commission
- Fonds De La Recherche Scientifique - FNRS
- Norges Forskningsråd
- European Climate, Infrastructure and Environment Executive Agency
- Horizon 2020 Framework Programme
- Natural Sciences and Engineering Research Council of Canada
- Japan Society for the Promotion of Science
- Core Research for Evolutional Science and Technology