A team of researchers from the WSU (Washington State University) have discovered that dams with their water reservoirs, nowadays universally considered green energy resources, are actually contributing to the heating of the global climate. How? Read on.
Methane, as it’s well-known, is 25 times more powerful than carbon dioxide when it comes to its greenhouse-causing properties. Bridget Deemer and Maria Galvin, both students at WSU-Vancouver measured the concentration of dissolved gases in Lacamas Lake in Clark County.
What Deemer found out was surprising: the methane emissions had been 20 times higher when the water level was drawn down. Galvin, on the other hand, measured 36-fold increases in methane in the sampled bubbles rising from the lake mud during a drawdown.
The United States counts up to 80,000 dams, and they’ve been looked at as a green energy resource. However, they play a big role in methane emissions and offset the benefits of carbon-free energy generation. A study published in 2011 says that terrestrial ecosystems as carbon sinks could account for 25% less than previously thought, if you also count in the emissions from reservoirs.
This is by far not the end of hydroelectric dams. By knowing how they work and how their ecosystems respond to various changes, scientists could define for the future a set of rules that would apply to dams and we’ll know how to use them to minimize the associated methane emissions.