New study confirms large dams to be a principle source of greenhouse gas emissions

October 5, 2016

Researchers from the Washington State University found that the world’s reservoirs generate 1.3 percent of all greenhouse gases produced by humankind. The finding confirms once more than large dams are unsustainable energy sources that cause great harm to the climate. 

Seattle, United States. An important new study by researchers at the Washington State University found that large dams are an “underestimated” source of greenhouse gas. The findings show that all reservoirs, not only those built in tropical zones, release far greater quantities of emissions into the atmosphere than previously believed.  

According to the study, gases are released from the decomposition of organic matter after artificial reservoirs flood natural areas. In fact, over the course of a year reservoirs were found to generate 1.3 percent of the world’s greenhouse gases (more than all of Canada). Eighty percent of those emissions were methane, a pollutant 34 times stronger than carbon dioxide.

“Across the Americas, governments are pushing for the construction of hundreds of new large dams, arguing that dams are clean energy and will help to mitigate climate change,” explained Astrid Puentes Riaño, co-director of the Interamerican Association for Environmental Defense (AIDA). “It’s become increasingly clear that large dams are more of a problem than a solution. World leaders must urgently start to plan and implement alternative energy solutions in order to achieve real progress in the fight against climate change.”

Along with a coaltion of civil society organizations, AIDA, Amazon Watch and International Rivers have been insisting for years that operating large hydroelectric projects—such as the Belo Monte Dam in Brazil—causes severe damage to the environment, the climate, and the rights of affected communities.

“Large dams are one of the most significant causes of environmental destruction in the Amazon,” said Leila Salazar-López, executive director of Amazon Watch. “In addition to emiting methane, they destroy biodiversity and the ancestral forest of thousands of indigenous and traditional communities that have lived for centuries from river ecosystems. It is imperative to calculate the true costs of large dams to understand all their impacts, and avoid causing more harm than good.”

As organizations working to promote real solutions to climate change, we are committed to sharing scientific evidence about the harms of large dams to governments, international bodies, and financial institutions.

"The new findings lay to rest the myth of hydropower as a clean source of electricity and underline why large hydropower should not receive climate finance," said Kate Horner, executive director of International Rivers.

The results of Washington State University's  study must be considered in the inventory of emissions that contribute to climate change, as well as in the execution of program and plans aimed at solving energy needs.

For more information consult:

  • Washington State University's study.
  • Washington State University’s press release on the study.
  • Short video from Astrid Puentes Riaño, AIDA co-director, with a brief explanation of the research and why it is important.
  • Our Manifesto on 10 reasons why climate initiatives should not include large dams.
  • An open letter to governments, international institutions and financial mechanisms to stop considering large dams as clean energy and to implement real solutions to climate change.