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Measurement of greenhouse gas emissions from U.S. reservoirs improves annual emissions inventory


U.S. reservoirs being sampled for the Survey of Reservoir Greenhouse gas Emissions (SuRGE). Source: EPA.

Emissions inventories that identify each country's sources and sinks of anthropogenic greenhouse gases are essential tools for addressing climate change. In accordance with the United Nations Framework Convention on Climate Change, the U.S. Government develops an annual report that tracks U.S. greenhouse gas emissions and sinks by source, economic sector, and greenhouse gas, going back to 1990. Emissions from reservoirs used for water storage are included in these inventories, since reservoirs are human made; after lands are flooded through construction of a dam, decomposition of organic matter and accumulation of upstream sediment produces the greenhouse gases carbon dioxide and methane. 

To improve incorporation of this data into the annual emissions survey, scientists at EPA, USGS, and DOE are collaborating to measure carbon dioxide and methane emissions from 108 U.S. reservoirs. The Survey of Reservoir Greenhouse Gas Emissions(SuRGE), taking place from 2020 through 2023, will inform a greater understanding of the amount of greenhouse gases emitted from U.S. reservoirs and the environmental factors that determine the rate of these emissions. For the first time, the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990–2020, published in 2022, included carbon dioxide and methane emissions from lands converted to use as reservoirs and other constructed water bodies. Additional survey results will inform future research modeling efforts and provide information to help managers improve water quality while helping to reduce greenhouse gas emissions.