Wildfires offset the increasing but spatially heterogeneous Arctic–boreal CO2 uptake

1172 Ympäristötiede, 1171 Geotieteet

This work was supported by funding from the Gordon and Betty Moore Foundation (grant number 8414; A.-M.V., B.M.R., J.D.W., S.P., S.M.N., K.A.A. and I.W.) and funding catalysed by the TED Audacious Project (Permafrost Pathways; A.-M.V., B.M.R., J.D.W., S.P., S.M.N., K.A.A. and I.W.). We additionally acknowledge funding from the NASA Arctic-Boreal Vulnerability Experiment and Carbon Cycle Science programmes (grant number NNX17AE13G; B.M.R.); NSF PLR Arctic System Science Research Networking Activities (grant number 1931333; E.A.G.S. and M. Mauritz); Minderoo Foundation (E.A.G.S.); NSF (grant numbers DEB LTREB 1354370, 2011257, DEB-0425328, DEB-0724514 and DEB-0830997; E.S.E. and C.W.E.); the US Geological Survey Climate R&D Program (E.S.E., M.S.B.-H. and C.W.E.); NSF Arctic Observatory Network (grant number 1936752; M.S.B.-H.; and grant numbers 1503912 and 1107892; E.S.E., M.S.B.-H. and C.W.E.); Office of Polar Programs of the NSF (award numbers 2149988 and 1932900; D.Z.); KAKENHI (grant number 19H05668; M.U.); the Danish National Research Foundation (CENPERM DNRF100; B.E.); EU HORIZON GreenFeedBack, grant agreement number 101056921 (I.M., M.G., E.L.-B., T.R.C. and M. Mastepanov) and LiweFor number 101079192 (I.M.); ICOS-FI via University of Helsinki funding (I.M.); Danish Arctic Climate support through Greenland Ecosystem Monitoring and ICOS grants (E.L.-B., T.R.C. and M. Mastepanov); Natural Sciences and Engineering Research Council (NSERC; V.L.S.L. and C.A.E.); the Deutsche Forschungsgemeinschaft (German Research Foundation) under Germany’s Excellence Strategy—EXC 2037 ‘CLICCS—Climate, Climatic Change, and Society’—project number 390683824 (L.K. and D.H.); Met Office Hadley Centre Climate Programme funded by DSIT and European Union’s Horizon 2020 research and innovation programme under Grant Agreement Number 101003536 (ESM2025—Earth System Models for the Future; E.J.B.); NASA Grant/Cooperative Agreement No. NNX17AD69A (A.C.); the Research Council of Norway (BioGov, project no. 323945; F.-J.W.P.); European Research Council (ERC synergy project Q-Arctic, grant agreement number 951288; M.G.); the Copernicus Atmosphere Monitoring Service, implemented by ECMWF on behalf of the European Commission (grant number CAMS2 55; F.C.); the Environment Research and Technology Development Fund of the Environmental Restoration and Conservation Agency of Japan (grant number JPMEERF21S20810; Y.N.); ArCSII (grant no. JPMXD142031886; M.U. and H.K.); the Swedish Research Council (VR) and consortium partners to ICOS Sweden (grant numbers 2015–06020 and 2019–00205; M.P. and M.B.N.) and SITES (grant number 2017–00635; M.P. and M.B.N.); VR grant numbers 2019-04676 and 2018-03966 (M.P. and M.B.N.); ArcticNet and NSERC (W.Q.); NOAA Cooperative Agreement NA16SEC4810008 (W.O.); Research Council of Finland (project numbers 341349, 330840, 349503 ICOS-FIRI and ACCC—Atmosphere and Climate Competence Center; I.M., M.E.M. and E.-S.T.); NRF-2021M1A5A1065425 (KOPRI-PN24011; S.-J.P.); NRF-2021M1A5A1065679 (N.C.); NRF-2021R1I1A1A01053870 (N.C.); the Dutch Research Council (NWO) (project number VI.Vidi.213.143; I.T.L.); the UK National Centre for Earth Observation funded by the National Environment Research Council (grant number NE/R016518/1) and the UK Space Agency (L.F. and P.I.P.); Ministry of Economic Development and Commerce of the Russian Federation (registration number 123030300031-6; A.V., R.P., T.C.M. and S.V.K.); NSF OPP 1936752 (M.S.B.-H.); NSERC Discovery Grant (M.H.); Helmholtz Association in the framework of MOSES (Modular Observation Solutions for Earth Systems; J.B.); and the Natural Environment Research Council through the National Centre for Earth Observation (grant number NE/R000115/1; L.F.). Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004; A.C. and J.L.). Part of the inverse analyses were performed on the supercomputer systems at the National Institute for Environmental Studies and Meteorological Research Institutes (NEC SX-Aurora TSUBASA and FUJITSU PRIMERGY CX2550M5; Y.N.) and at the HPC cluster Aether at the University of Bremen, financed by the Deutsche Forschungsgemeinschaft within the scope of the Excellence Initiative (Germany; I.T.L.). We further thank the Arctic Data Center Working Group: Reconciling historical and contemporary trends in terrestrial carbon exchange of the northern permafrost-zone, and we thank R. Treharne, T. Smith and Y. Yang for help with the analysis.

The in situ data used here can be accessed via ORNL DAAC (https://doi.org/10.3334/ORNLDAAC/1934)77, and the geospatial data are available via the links and references provided in Supplementary Tables 3 and 6. The 1-km upscaled rasters of NEE, GPP and Reco are available via ORNL DAAC (https://doi.org/10.3334/ORNLDAAC/2377)78. The analysis code is available via Zenodo at https://doi.org/10.5281/zenodo.13691584 (ref. 61).