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Reservoir CO2 and CH4 emissions and their climate impact over the period 1900–2060


Reservoirs are essential for human populations, but their global carbon footprint is substantial (0.73–2.41 PgCO2-equivalent yr−1). Yet the temporal evolution of reservoir carbon emissions and their contribution to anthropogenic radiative forcing remains unresolved. Here we quantify the long-term historical and future evolution (1900–2060) of cumulative global reservoir area, carbon dioxide and methane emissions and the resulting radiative forcing. We show that global reservoir carbon emissions peaked in 1987 (4.4 TmolC yr−1) and have been declining since, due largely to decreasing carbon dioxide emissions as reservoirs age. However, reservoir-induced radiative forcing continues to rise due to ongoing increases in reservoir methane emissions, which accounted for 5.2% of global anthropogenic methane emissions in 2020. We estimate that, in the future, methane ebullition and degassing flux will make up >75% of the reservoir-induced radiative forcing, making these flux pathways key targets for improved understanding and mitigation.

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Fig. 1: Evolution of reservoir area.
Fig. 2: Reservoir emissions through time.
Fig. 3: Relative contribution of reservoirs to anthropogenic carbon emissions.
Fig. 4: Evolution of reservoir-induced RF.
Fig. 5: Relative contribution of RF of each reservoir flux pathway compared with global anthropogenic RF of combined C-GHGs, CO2 and CH4.

Data availability

Data and modelling tools used in this study are available through the following sources: GRanD v.1.3 database38, Zarfl, Lumsdon et al. (2015)15, G-res tool10, MAGICC626, SSP public database v.2.036. A year-by-year dataset of reservoir area and emissions is also available in Supplementary Data 1.


  1. St. Louis, V. L., Kelly, C. A., Duchemin, É., Rudd, J. W. M. & Rosenberg, D. M. Reservoir surfaces as sources of greenhouse gases to the atmosphere: a global estimate. Bioscience 50, 766–775 (2000).

    Article  Google Scholar 

  2. Roland, F. et al. Variability of carbon dioxide flux from tropical (Cerrado) hydroelectric reservoirs. Aquat. Sci. 72, 283–293 (2010).

    Article  Google Scholar 

  3. Barros, N. et al. Carbon emission from hydroelectric reservoirs linked to reservoir age and latitude. Nat. Geosci. 4, 593–596 (2011).

    Article  Google Scholar 

  4. Deemer, B. R. et al. Greenhouse gas emissions from reservoir water surfaces: a new global synthesis. Bioscience 66, 949–964 (2016).

    Article  Google Scholar 

  5. Hertwich, E. G. Addressing biogenic greenhouse gas emissions from hydropower in LCA. Environ. Sci. Technol. 47, 9604–9611 (2013).

    Article  Google Scholar 

  6. Harrison, J. A., Prairie, Y. T., Mercier‐Blais, S. & Soued, C. Year‐2020 global distribution and pathways of reservoir methane and carbon dioxide emissions according to the Greenhouse Gas from Reservoirs (G‐res) model. Glob. Biogeochem. Cycles 35, 1–14 (2021).

    Article  Google Scholar 

  7. Bastviken, D., Tranvik, L. J., Downing, J. A., Crill, P. M. & Enrich-Prast, A. Freshwater methane emissions offset the continental carbon sink. Science 331, 50 (2011).

    Article  Google Scholar 

  8. Rosentreter, J. A. et al. Half of global methane emissions come from highly variable aquatic ecosystem sources. Nat. Geosci. 14, 225–230 (2021).

    Article  Google Scholar 

  9. Johnson, M. S. et al. Spatiotemporal methane emission from global reservoirs. J. Geophys. Res. Biogeosci. (2021).

  10. Prairie, Y. T. et al. A new modelling framework to assess biogenic GHG emissions from reservoirs: the G-res tool. Environ. Model. Softw. 143, 105117 (2021).

    Article  Google Scholar 

  11. Deemer, B. R. & Holgerson, M. A. Drivers of methane flux differ between lakes and reservoirs, complicating global upscaling efforts. J. Geophys. Res. Biogeosci. 126, e2019JG005600 (2021).

    Article  Google Scholar 

  12. Abril, G. et al. Carbon dioxide and methane emissions and the carbon budget of a 10-year old tropical reservoir (Petit Saut, French Guiana.). Glob. Biogeochem. Cycles 19, GB4007 (2005).

    Article  Google Scholar 

  13. Teodoru, C. R. et al. The net carbon footprint of a newly created boreal hydroelectric reservoir. Global Biogeochem. Cycles 26, GB2016 (2012).

    Article  Google Scholar 

  14. Yan, X., Thieu, V. & Garnier, J. Long-term evolution of greenhouse gas emissions from global reservoirs. Front. Environ. Sci. (2021).

  15. Zarfl, C., Lumsdon, A. E., Berlekamp, J., Tydecks, L. & Tockner, K. A global boom in hydropower dam construction. Aquat. Sci. 77, 161–170 (2015).

    Article  Google Scholar 

  16. Keller, P. S., Marcé, R., Obrador, B. & Koschorreck, M. Global carbon budget of reservoirs is overturned by the quantification of drawdown areas. Nat. Geosci. 14, 402–408 (2021).

    Article  Google Scholar 

  17. Facts About Hydropower (International Hydropower Association, 2022);

  18. Prairie, Y. T. et al. Greenhouse gas emissions from freshwater reservoirs: what does the atmosphere see? Ecosystems 21, 1058–1071 (2018).

    Article  Google Scholar 

  19. Galy-Lacaux, C., Delmas, R., Kouadio, G., Richard, S. & Gosse, P. Long-term greenhouse gas emissions from hydroelectric reservoirs in tropical forest regions. Glob. Biogeochem. Cycles 13, 503–517 (1999).

    Article  Google Scholar 

  20. Venkiteswaran, J. J. et al. Processes affecting greenhouse gas production in experimental boreal reservoirs. Glob. Biogeochem. Cycles 27, 567–577 (2013).

    Article  Google Scholar 

  21. Matthews, C. J. D. et al. Carbon dioxide and methane production in small reservoirs flooding upland boreal forest. Ecosystems 8, 267–285 (2005).

    Article  Google Scholar 

  22. Yvon-Durocher, G. et al. Methane fluxes show consistent temperature dependence across microbial to ecosystem scales. Nature 507, 488–491 (2014).

    Article  Google Scholar 

  23. Beaulieu, J. J., DelSontro, T. & Downing, J. A. Eutrophication will increase methane emissions from lakes and impoundments during the 21st century. Nat. Commun. 10, 3–7 (2019).

    Article  Google Scholar 

  24. Soued, C. & Prairie, Y. T. The carbon footprint of a Malaysian tropical reservoir: measured versus modelled estimates highlight the underestimated key role of downstream processes. Biogeosciences 17, 515–527 (2020).

    Article  Google Scholar 

  25. Lee, D. S. et al. The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018. Atmos. Environ. 244, 117834 (2021).

    Article  Google Scholar 

  26. Meinshausen, M., Raper, S. C. B. & Wigley, T. M. L. Emulating coupled atmosphere–ocean and carbon cycle models with a simpler model, MAGICC6 – part 1: model description and calibration. Atmos. Chem. Phys. 11, 1417–1456 (2011).

    Article  Google Scholar 

  27. Myhre, G. et al. in Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) 659–740 (Cambridge Univ. Press, 2013).

  28. Ocko, I. B. et al. Unmask temporal trade-offs in climate policy debates. Science 356, 492–493 (2017).

    Article  Google Scholar 

  29. Encinas Fernández, J., Hofmann, H. & Peeters, F. Diurnal pumped-storage operation minimizes methane ebullition fluxes from hydropower reservoirs. Water Resour. Res. 56, e2020WR027221 (2020).

    Article  Google Scholar 

  30. Nash, J. E. & Sutcliffe, J. V. River flow forecasting through conceptual models part I—a discussion of principles. J. Hydrol. 10, 282–290 (1970).

    Article  Google Scholar 

  31. Lehner, B. et al. High-resolution mapping of the world’s reservoirs and dams for sustainable river-flow management. Front. Ecol. Environ. 9, 494–502 (2011).

    Article  Google Scholar 

  32. Lovelock, C. E. et al. in 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories Vol. 4 (eds Agus, F. et al.) Ch. 7 (TFI, 2019).

  33. Rubel, F. & Kottek, M. Observed and projected climate shifts 1901–2100 depicted by world maps of the Koppen–Geiger climate classification. Meteorol. Zeitschrift 19, 135–141 (2010).

    Article  Google Scholar 

  34. Ubierna, M., Diez Santos, C. & Mercier-Blais, S. in Water Security Under Climate Change (eds Biswas, A. & Tortajada, C.) 69–94 (Springer, 2021);

  35. Ciais, P. et al. in Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) 465–570 (Cambridge Univ. Press, 2013);

  36. SSP Database Version 2.0 (IIASA, 2018):

  37. Etminan, M., Myhre, G., Highwood, E. J. & Shine, K. P. Radiative forcing of carbon dioxide, methane, and nitrous oxide: a significant revision of the methane radiative forcing. Geophys. Res. Lett. 43, 12614–12623 (2016).

    Article  Google Scholar 

  38. Lehner, B. et al. Global Reservoir and Dam (GRanD) database. Global Dam Watch (2011).

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This study was funded by the UNESCO Chair in Global Environmental Change held by Y.T.P. through which C.S., S.M.-B. and Y.T.P. were funded. J.A.H. was funded by an NSF INFEWS grant (NSF EAR 1639458), an NSF DEB Grant (no. 135211), a GRIL Fellowship Grant and a Stanford University Cox Visiting Professorship.

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All authors contributed to conceptualization and data analysis. S.M.-B. performed data curation. J.A.H. and Y.T.P. acquired funding. C.S. wrote the original draft, and all authors reviewed and edited the manuscript.

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Correspondence to Cynthia Soued.

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Nature Geoscience thanks Xingchen Yan, Lluís Gómez-Gener, Ronny Lauerwald and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Thomas Richardson, in collaboration with the Nature Geoscience team.

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Soued, C., Harrison, J.A., Mercier-Blais, S. et al. Reservoir CO2 and CH4 emissions and their climate impact over the period 1900–2060. Nat. Geosci. 15, 700–705 (2022).

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