The carbon balance of peatlands is predicted to shift from a sink to a source this century. However, peatland ecosystems are still omitted from the main Earth system models that are used for future climate change projections, and they are not considered in integrated assessment models that are used in impact and mitigation studies. By using evidence synthesized from the literature and an expert elicitation, we define and quantify the leading drivers of change that have impacted peatland carbon stocks during the Holocene and predict their effect during this century and in the far future. We also identify uncertainties and knowledge gaps in the scientific community and provide insight towards better integration of peatlands into modelling frameworks. Given the importance of the contribution by peatlands to the global carbon cycle, this study shows that peatland science is a critical research area and that we still have a long way to go to fully understand the peatland–carbon–climate nexus.
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Data supporting the findings of this study, as well as references used to generate the maps, are available within the supplementary information files. All anonymized survey data generated and analysed during this study are available from the corresponding authors upon request.
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This work developed from the PAGES (Past Global Changes) C-PEAT (Carbon in Peat on EArth through Time) working group; we acknowledge support from PAGES funding by the American and Swiss National Science Foundations. We also thank the International Union for Quaternary Research (INQUA) and the Department of Geography at Texas A&M University for workshop support. We thank P. Campbell for creating the peatland infographic, as well as D. McGuire for his comments on a previous version of the manuscript. We also acknowledge research support from Universidad Javeriana (J.C.B.); the National Science Foundation of the United States under grant nos. 1802838 (J. Loisel), 1019523 (J.L.B.) and 1802825 (C.T. and S.F.); the National Environment Research Council of the United Kingdom under grant nos. NE/1012915 and NE/S001166/1 (A.V.G.-S. and D.J.C.); the Attraction and Insertion of Advanced Human Capital Program of the National Commission for Scientific and Technological Research of Chile and the NEXER-UMAG project under grant no. 7718002 (C.A.M.); the Geological Survey Land Resources Research and Development program of the United States (M.C.J.); the Natural Sciences and Engineering Research Council of Canada (M. Garneau, S.F., T. Lacourse and J.W.); the National Science Centre of Poland under grant no. 2015/17/B/ST10/01656 (M.L.); the Academy of Finland projects 286731 and 319262 (T. Larmola); the Belgian National Fund for Scientific Research under grant no. 1167019N (W.S.); the Office of International Affairs and Global Network at Chulalongkorn University (S.C.); the Alexander von Humboldt Foundation of Germany (M.B.); the Accelerating Higher Education Expansion and Development and Development Oriented Research programs of the World Bank (A.S.R.); and the Swiss National Science Foundation under grant no. 200020_172476 (F.J. and J.M.).
The authors declare no competing interests.
Peer review information Nature Climate Change thanks Katharine Mach and Matthew Warren for their contribution to the peer review of this work.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Each individual response is shown as a spot. Positive values represent peatland sinks, negative values represent peatland sources to the atmosphere. When a range of values was given, the midpoint is used. Codes for drivers: T = temperature, M = moisture balance, SL = sea level, F = fire, LU = land use, P = permafrost, N = nitrogen deposition, AP = atmospheric pollution.
Extended Data Fig. 2 All self-reported confidence and expertise levels, organized by time period and peatland region.
Blue (yellow) bars represent high-latitude (tropical) peatlands. Confidence and expertise values specified in the survey were 1 = very low, 2 = low, 3 = medium, 4 = high, 5 = very high.
Extended Data Fig. 3 Comparison of survey results from all respondents vs. those from highly self-rated experts.
Data shown as mean and 10th – 90th percentiles. High-latitude peatland results shown in blue (dark = all data, light = E>2). Tropical peatland data shown in yellow (dark yellow = all data, light beige = E>2). Positive values represent peatland sinks, negative values represent peatland sources to the atmosphere. Codes for drivers: T = temperature, M = moisture balance, SL = sea level, F = fire, LU = land use, P = permafrost, N = nitrogen deposition, AP =atmospheric pollution.
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Loisel, J., Gallego-Sala, A.V., Amesbury, M.J. et al. Expert assessment of future vulnerability of the global peatland carbon sink. Nat. Clim. Chang. 11, 70–77 (2021). https://doi.org/10.1038/s41558-020-00944-0