The construction of dams, depending on their type and size, [emits] significant amounts of greenhouse gases (GHG).
Dam construction involves the displacement of large amounts of solid material following blasting and excavation of rocks, gravel and sand. It also requires the manufacturing of cement, a process that leads to chemically induced emissions of CO2 to the atmosphere. Material and matter are transported by trucks [and other fossil-fuel powered vehicles], which in turn cause additional GHG emissions.
Source: Global Warming and Hydroelectric Reservoirs, p. 34 (COPPE/UFRJ, Eletrobras, 2005; dos Santos & Rosa, Eds).
Please also read the International Rivers report “Fizzy Science: Loosening the Hydro Industry’s Grip on Reservoir Greenhouse Gas Emissions Research”
Learn more about how climate change, dams and rivers interact.