Over-Fertilizing the Ozone Layer
Scientists Complete New Study on Nitrous Oxide Emissions
Sep 18, 2009
The report's scientists claim that nitrous oxide is presently the largest ozone-depleting substance emitted through human activities and will continue to do so for many decades. About one-third of global nitrous oxide emissions are anthropogenic (caused by human activities).
National Oceanic and Atmospheric Administration
The study, which was authored by A.R. Ravishankara, J.S. Daniel and Robert W. Portmann of NOAA's Earth System Research Laboratory chemical sciences division appeared in August 2009, in the journal Science. This group tracks the thickness of the ozone layer as well as processes that improve the understanding of ozone depletion and the potential recovery of the ozone layer. "There's so much being emitted, that right now, nitrous oxide emissions would be the largest ozone-depleting gas emissions today, and it will continue to be in the future," says Ravishankara.
The good news: there has been a dramatic reduction in chlorofluorocarbons (CFCs) over the last 20 years since they were phased out internationally. (The ozone layer was being depleted by CFCs in synthetic chemicals used in aerosol spray cans, refrigerators and air conditioners.)
The bad news: nitrous oxide emissions from human activities are more than twice as high as the next leading ozone-depleting gas.
What's the Ozone Layer Got to Do With It?
The ozone layer helps to shield people, animal and plants from too much ultraviolet light from the sun. Thinning of the ozone layer allows more ultraviolet light in where it can severely damage human health, aquatic life and plants. Nitrous oxide is also a greenhouse gas so not only does it hurt the ozone layer but reducing it could also help with climate change.
What's Fertilizing the Petunias Got to Do With It?
Nitrous oxide is produced naturally from a variety of biological sources in water and soil. According to the EPA, primary human-related sources of nitrous oxide are agricultural soil management, animal manure management, sewage treatment, mobile and stationary combustion of fossil fuel, and nitric acid production.
While scientists figure out the solution to help the ozone layer repair itself, home gardeners and farmers could help by using less fertilizer, especially ones high in nitrogen. Lawn fertilizers have a high nitrate rate so many master gardeners suggest only fertilizing your lawn once in the spring and again in the fall, and preferably with an organic fertilizer or compost.
Methane, the Other Troublemaker
Close to 40 percent of landfills are filled with compostable materials that are producing methane, a gas 34 times more potent than carbon dioxide and the second-leading greenhouse gas emitted in the United States. According to the Environmental Protection Agency (EPA), landfill methane emissions are the largest source of anthropogenic (human-related) methane emissions in the nation.
Governments globally will have to work quickly to enact policies that curb anthropogenic nitrous oxide and methane to help save the ozone-layer and fight climate change.
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