The growing role of farming and nitrous oxide in climate change

By Carol Clark | eScienceCommons | Oct. 10, 2013

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A farmer fertilizes his field in India, where consumption of nitrogen from fertilizer has shot up by 50 percent during the past 10 years.

Most people know nitrous oxide as laughing gas, used as a mild anesthetic for dental patients. What's less well-known is that nitrous oxide is the leading cause of the depletion of the protective layer of ozone in the Earth's atmosphere, and the third-largest greenhouse gas, after carbon dioxide and methane.

"Not many people know about the impact of nitrous oxide, and very few people are studying the nitrogen cycle," says Eri Saikawa, an assistant professor in Emory's Department of Environmental Studies.

Nitrous oxide is released naturally from the soil, as part of the process of microbes breaking down nitrogen. However, human activity, especially agriculture, has boosted the emission levels in recent decades. Livestock manure and fertilizers containing nitrates, ammonia or urea all generate nitrous oxide as they decompose.

"Nitrous oxide emissions stay in the atmosphere for 125 years, similar to carbon dioxide. So it's very important that we take action now," Saikawa says.

Saikawa, whose research is focused on emissions linked to air pollution, ozone depletion and global warming, will give an overview of her work on nitrous oxide as part of Environmental Studies' fall lecture series. Her talk, "Laughing Gas: No Laughing Matter for Climate Change and the Environment," is set for 4 pm on Monday, October 21 in the Math and Science Center, room N306.

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