Greenhouse Gas Emissions from Reservoir Water Surfaces: A New Global Synthesis

Deemer, Bridget R.
Harrison, John A.
Li, Siyue
Beaulieu, Jake J.
DelSontro, Tonya
Barros, Nathan
Bezerra-Neto, José F.
Powers, Stephen M.
dos Santos, Marco A.
Vonk, Arie J.

Bridget R. Deemer ([email protected]) and John A. Harrison are affiliated with the School of the Environment at Washington State University, in Vancouver. Siyue Li is with the Chongqing Institute of Green and Intelligent Technology at the Chinese Academy of Sciences, in Chongqing, China. Jake J. Beaulieu is affiliated with the US Environmental Protection Agency's Office of Research and Development and National Risk Management Research Laboratory, in Cincinnati, Ohio. Tonya DelSontro is with the Department of Biological Sciences at the University of Québec at Montréal, in Canada, and was formerly at the Swiss Federal Institute of Aquatic Science and Technology (Eawag), Kastanienbaum, Switzerland. Nathan Barros is affiliated with the Institute of Biological Sciences at the Federal University of Juiz de Fora, in Minas Gerais, Brazil. José F. Bezerra-Neto is with the Institute of Biological Sciences at the Federal University of Minas Gerais, in Belo Horizonte, Minas Gerais, Brazil. Stephen M. Powers is with the School of the Environment and the Center for Environmental Research, Education, and Outreach at Washington State University, in Pullman. Marco A. dos Santos is with the Energy Planning Program, COPPE, and Centro de Tecnologia at the Federal University of Rio de Janeiro, in Brazil. J. Arie Vonk is affiliated with the Department of Aquatic Environmental Ecology of the Institute for Biodiversity and Ecosystem Dynamics at the University of Amsterdam, in The Netherlands

Bioscience 66(11):p 949-964, November 2016. | DOI: 10.1093/biosci/biw117

Collectively, reservoirs created by dams are thought to be an important source of greenhouse gases (GHGs) to the atmosphere. So far, efforts to quantify, model, and manage these emissions have been limited by data availability and inconsistencies in methodological approach. Here, we synthesize reservoir CH₄, CO₂, and N₂O emission data with three main objectives: (1) to generate a global estimate of GHG emissions from reservoirs, (2) to identify the best predictors of these emissions, and (3) to consider the effect of methodology on emission estimates. We estimate that GHG emissions from reservoir water surfaces account for 0.8 (0.5–1.2) Pg CO₂ equivalents per year, with the majority of this forcing due to CH₄. We then discuss the potential for several alternative pathways such as dam degassing and downstream emissions to contribute significantly to overall emissions. Although prior studies have linked reservoir GHG emissions to reservoir age and latitude, we find that factors related to reservoir productivity are better predictors of emission.