A team of researchers from Canada, Holland, China, the U.S. and Brazil “found that greenhouse gas emissions from man-made reservoirs were likely equal to the equivalent of one gigaton of carbon dioxide being released into the atmosphere every year…a little less than one-sixth of the United State’s greenhouse gas emissions.” An anonymous Slashdot reader quotes Popular Science:
A reservoir is usually created by damming a river, overflowing the banks and flooding the surrounding area, creating a man-made lake…the perfect conditions for microbes to generate greenhouse gases like carbon dioxide and methane (a gas that is about 25 times more potent than carbon dioxide)… “When reservoirs are first flooded there’s organic matter in the soil and vegetation that can be converted by microbes into methane and carbon dioxide,” John Harrison, a co-author of the paper, tells Popular Science.
“Also, reservoirs because they are in line in rivers, they receive a lot of organic matter and organic sediment from upstream that can fuel the production of methane, carbon dioxide and nitrous oxide.” Harrison says that reservoirs also tend to occur in areas where fertilizers are used on the surrounding land. Runoff from those fertilizers into bodies of water can cause algal blooms that can also produce more methane and carbon dioxide.
If the world’s reservoirs were a country, they’d be #8 on a list of polluters — right behind Brazil, China, the EU and the U.S.
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