Tuesday, December 21, 2010

Global rivers release huge amounts of nitrous oxide, a potent greenhouse gas

Live Science: Rivers may be a significant source of the greenhouse gas nitrous oxide, scientists now find. Their calculation suggests that across the globe the waterways contribute three times the amount of nitrous oxide to the atmosphere as had been estimated by the International Panel on Climate Change (IPCC), the United Nations scientific body charged with reviewing climate change research.

They found that the amount of nitrous oxide produced in streams is related to human activities that release nitrogen into the environment, such as fertilizer use and sewage discharges. "Human activities, including fossil fuel combustion and intensive agriculture, have increased the availability of nitrogen in the environment," said Jake Beaulieu of the University of Notre Dame and the U.S. Environmental Protection Agency in Cincinnati, Ohio, and lead author of the paper published this week in the journal Proceedings of the National Academy of Sciences.

…The finding is important, the researchers say, because nitrous oxide is a potent greenhouse gas that contributes to climate change and destruction of the stratosphere's ozone layer, which protects us from the sun's harmful ultraviolet radiation. Compared with carbon dioxide, nitrous oxide is 300-fold more potent in terms of its warming potential, though carbon dioxide is a far more prevalent greenhouse gas. Scientists estimate nitrous oxide accounts for about 6 percent of human-induced climate change.

…"Changes in agricultural and land-use practices that result in less nitrogen being delivered to streams would reduce nitrous oxide emissions from river networks," Beaulieu said.

Poole Harbor in Dorset at sunset, shot by Petr Kratochvil, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

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