Hydroelectric reservoirs cover an area of 3.4×105 km2 and comprise about 20% of all reservoirs. In addition, they contain large stores of formerly terrestrial organic carbon. Significant amounts of greenhouse gases are emitted2, especially in the early years following reservoir creation, but the global extent of these emissions is poorly known. Previous estimates of emissions from all types of reservoir indicate that these human-made systems emit 321 Tg of carbon per year (ref. 4). Here we assess the emissions of carbon dioxide and methane from hydroelectric reservoirs, on the basis of data from 85 globally distributed hydroelectric reservoirs that account for 20% of the global area of these systems. We relate the emissions to reservoir age, location biome, morphometric features and chemical status. We estimate that hydroelectric reservoirs emit about 48 Tg C as CO2 and 3 Tg C as CH4, corresponding to 4% of global carbon emissions from inland waters. Our estimates are smaller than previous estimates on the basis of more limited data. Carbon emissions are correlated to reservoir age and latitude, with the highest emission rates from the tropical Amazon region. We conclude that future emissions will be highly dependent on the geographic location of new hydroelectric reservoirs.
This is a preview of subscription content, access via your institution
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Rent or buy this article
Prices vary by article type
Prices may be subject to local taxes which are calculated during checkout
Chao, B. F., Wu, Y. H. & Li, Y. S. Impact of artificial reservoir water impoundment on global sea level. Science 320, 212–214 (2008).
Rudd, J. W. M., Harris, R., Kelly, C. A. & Hecky, R. E. Are hydroelectric reservoirs significant sources of greenhouse gases? Ambio 22, 246–248 (1993).
Pircher, W. 36000 dams and still more needed. Intern. Water Power Dam Construction 45, 15–18 (1993).
St Louis, V. L., Kelly, C. A., Duchemin, E., 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).
Giles, J. Methane quashes green credentials of hydropower. Nature 444, 524–525 (2006).
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).
Teodoru, C., Prairie, Y. & del Giorgio, P. Spatial heterogeneity of surface CO2 fluxes in a newly created Eastmain-1 reservoir in Northern Quebec, Canada. Ecosystems 14, 28–46 (2010).
Fearnside, P. M. Brazil’s Samuel Dam: Lessons for hydroelectric development policy and the environment in Amazonia. Environ. Manage. 35, 1–19 (2005).
DelSontro, T., McGinnis, D. F., Sobek, S., Ostrovsky, I. & Wehrli, B. Extreme methane emissions from a Swiss hydropower reservoir: Contribution from bubbling sediments. Environ. Sci. Technol. 44, 2419–2425 (2010).
Tremblay, A., Lambert, M. & Gagnon, L. Do hydroelectric reservoirs emit greenhouse gases? Environ. Manage. 33, S509–S517 (2004).
Santos, M. A., Rosa, L. P., Sikar, B., Sikar, E. & Dos Santos, E. O. Gross greenhouse gas fluxes from hydro-power reservoir compared to thermo-power plants. Energy Policy 34, 481–488 (2004).
Kosten, S. et al. Climate-dependent CO2 emissions from lakes. Glob. Biogeochem. Cycles 24, GB2007 (2010).
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).
Bastviken, D., Cole, J., Pace, M. & Tranvik, L. Methane emissions from lakes: Dependence of lake characteristics, two regional assessments, and a global estimate. Glob. Biogeochem. Cycles 18, GB4009 (2004).
Roland, F. et al. Variability of carbon dioxide flux from tropical (Cerrado) hydroelectric reservoirs. Aquat. Sci. 72, 283–293 (2010).
Kemenes, A., Forsberg, B. R. & Melack, J. M. Methane release below a tropical hydroelectric dam. Geophys. Res. Lett. 34, L12809 (2007).
Guerin, F. et al. Methane and carbon dioxide emissions from tropical reservoirs: Significance of downstream rivers. Geophys. Res. Lett. 33, L21407 (2006).
IPCC Climate Change 2007: Synthesis Report (eds Pachauri, R. K. & Reisinger, A.) (IPCC, 2007).
Cole, J. J. et al. Plumbing the global carbon cycle: Integrating inland waters into the terrestrial carbon budget. Ecosystems 10, 171–184 (2007).
Tranvik, L. J. et al. Lakes and reservoirs as regulators of carbon cycling and climate. Limnol. Oceanogr. 54, 2298–2314 (2009).
Soumis, N., Duchemin, E., Canuel, R. & Lucotte, M. Greenhouse gas emissions from reservoirs of the western United States. Glob. Biogeochem. Cycles 18, GB3022 (2004).
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).
We thank F. Pacheco, R. Almeida and D. Torsten for searching data to improve our database. We are grateful to A. Cimbleris for inspiring us with insights connecting science and societal needs and to R. Mendonça and J. Ometto for critical discussion and reading of the manuscript. This work was supported by grants from FURNAS Centrais Elétricas and from the Swedish Foundation for International Cooperation in Research and Higher Education (STINT). V.L.M.H. and F.R. are partially supported by Conselho Nacional de Investigação Científica e Tecnológica (CNPq), Brasil.
The authors declare no competing financial interests.
About this article
Cite this article
Barros, N., Cole, J., Tranvik, L. et al. Carbon emission from hydroelectric reservoirs linked to reservoir age and latitude. Nature Geosci 4, 593–596 (2011). https://doi.org/10.1038/ngeo1211
This article is cited by
Current Pollution Reports (2023)
Environmental Science and Pollution Research (2023)
Greenhouse gas emissions from hydroelectric reservoirs: mechanistic understanding of influencing factors and future prospect
Environmental Science and Pollution Research (2023)
Florida’s urban stormwater ponds are net sources of carbon to the atmosphere despite increased carbon burial over time
Communications Earth & Environment (2022)