Hydropower is considered by many to be a key ingredient to reducing carbon emissions and meeting global climate goals,
but it comes at a great cost to biodiversity, particularly in tropical rainforests, according to a new report published in the journal Science. “Far too often in developing tropical countries, major hydropower projects have been approved and their construction begun before any serious assessments of environmental and socioeconomic impacts had been conducted,” says the report’s lead author Kirk Winemiller, an aquatic ecologist at Texas A&M University. The dam-building rush, with more than 450 dams planned for the Amazon, Congo, and Mekong river basins alone, impedes tropical fish migration and vastly expands deforestation due to road construction, according to the authors. Other concerns include development of previously inaccessible terrain, as well as methane emissions from newly built reservoirs.