Hydroelectricity discharges one billion tons of CO2 into the atmosphere every year

Dams and reservoirs that supply water for hydroelectricity are a huge source of greenhouse gases.

New research by Washington University scientists (WSU), USA, shows that dams and hydroelectric reservoirs are actually a major source of greenhouse gas emissions , Tech Times reported on October 3. The WSU team analyzed 200 previous reports of potential gas emissions from 267 dams and reservoirs worldwide, with a total area of ​​about 77,699 km ² .

The results showed that dams and reservoirs emit nearly 1 billion tons of carbon dioxide (CO2) each year into the atmosphere, equivalent to 1.3% of the total man-made greenhouse gases and greater than the total. Canadian greenhouse gas emissions.

Hydropower reservoirs are a major source of greenhouse gases.(Photo: Evgeny Vorobyev).

People build dams to prevent rivers, flooding areas around the sides. This process creates artificial lakes for power generation, water storage for agriculture or flood control. But dam construction also makes perfect conditions for microorganisms to grow, emitting greenhouse gases such as methane (CH ₄ ) and carbon dioxide. These gases bubbles on the surface of the reservoir, then enter the atmosphere.

According to Science Alert, it is worrisome that about 79% of the emissions from the reservoir are methane (a gas capable of warming the Earth 36 times more than carbon dioxide), 17% carbon dioxide and 4% nitrous oxide.

The author of the study, John Harrison, said methane is the gas with the least water solubility compared to the remaining greenhouse gases."In many reservoirs, you can see a lot of air bubbles floating above the water from below. They are usually methane gas , " Harrison said.

The amount of methane emissions per reservoir area unit is 25% higher than that of previous studies. This is a significant proportion, especially when the construction of dams around the world is constantly increasing, said Bridget Deemer, a member of the research team.