Monday, July 19, 2010

The forgotten footprint: Nitrogen

Madeline Bodin in the Times Argus (Vermont): You may know your carbon footprint, but do you know your nitrogen footprint? Nitrous oxide is 300 times more potent than carbon dioxide. Nitrogen has been pegged as an over-looked cause of climate change and as a culprit in some of the most insidious forms of environmental pollution.

“Nitrogen’s role as a greenhouse gas is mostly as nitrous oxide,” said Jeff Merrell, environmental analyst for the Vermont Agency of Natural Resource’s Air Pollution Control Division. Nitrous oxide is ranked as one of the leading causes of climate change. It’s one of six gases regulated by the Kyoto Protocol, an international climate change treaty. Nitrous oxide contributes to climate change by absorbing heat from the sun and holding it in the Earth’s atmosphere. “Nitrous oxide has 300 times more global warming potential than carbon dioxide,” Merrell said. But, he quickly adds, there is a reason why carbon dioxide gets all the attention: There is just so much more of it.

…According to the federal Environmental Protection Agency (EPA), more than 60 percent of the nitrous oxide emitted comes from natural sources, mostly from bacteria in the soil and the oceans. The leading human-created sources are fertilizers, the burning of fossil fuels in vehicles and power plants, the production of nylon, and the production of nitric acid (which is used to make fertilizers, explosives, and has other industrial applications). The EPA said the amount of nitrous oxide in the atmosphere has increased 16 percent in the last 250 years, and now increases at a rate of a quarter of a percent each year….

View of Cossingham Farm, near Bragg Hill Road in Norwich, Vermont in autumn, shot by HopsonRoad, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

1 comment:

s.d. savage said...

You are right that many people ignore nitrous oxide, but agricultural researchers have certainly not. The details of how and when fertilizers are used has a great deal to do with how much nitrous oxide is released. This link is just one recent set of studies on the topic
http://www.fertilizer.org/ifacontent/download/35324/510327/version/2/file/2010_ifa_newag_Halvorson_slides.pdf
Steve Savage, Ph.D.