Your carbon footprint has a shadow: nitrogen. Unlike carbon dioxide, which scientists have long understood as a damaging green house gas, nitrogen is still revealing its role on the stage of climate change. Despite the complexities that ultimately emerge in the interplay between nitrogen and other greenhouse gases--especially carbon dioxide--the nitrogen cycle is relatively straightforward. It is also essential to understand.
Nitrogen is one of the most vital elements in our atmosphere, though if overly abundant, it can have unexpected and hazardous consequences. As one of the most unstable elements in the solid earth, nitrogen is simultaneously one of the most stable elements in the atmosphere, where it builds up in what is called the Gaseous Atmospheric Nitrogen Store. Nitrogen is released into the atmosphere by naturally occurring processes like decomposing organic matter--rotting food, rotting plants, etc.
But the organic nitrogen cycle is currently off-balance due to the surplus created by human activities: fossil fuel emissions and fertilizer run-off are two of the most prominent sources of excess build up. Fossil fuels burn into the atmosphere, while nitrogen-based fertilizers run off into the ocean and both eventually become part of the atmospheric store of nitrogen. Sometimes, nitrogen is released from the atmosphere in natural processes like lightening and sometimes it comes down as acid rain.
Unpleasant as it is, acid rain is perhaps less of an issue than what's happening directly in the oceans. In addition to fertilizer run-off, other human-created nitrogen particles end up in the sea via wind. The properties that make nitrogen so effective for spurring flora and fauna across farms go to work in the water, creating an increase in marine plant life.
While oceanic plants play a big role in metabolizing carbon dioxide, thereby helping to reduce the damaging effect of this green house gas, they can only do their job when in balance with carbon dioxide levels. When too many plants flourish, a deficit of carbon dioxide results and nitrous oxide forms.
Nitrous oxide is then pushed out into the atmosphere as a greenhouse gas. According to Robert Duce, Distinguished Professor of Oceanography and Atmospheric Sciences at Texas A&M University, "If you don't consider the impact of human-caused nitrogen when trying to model climate change, you're missing a possibly significant part of the overall carbon cycle as well as the nitrogen cycle."
The delicate balance of carbon and nitrogen plays again in human activities. For example, Peter Vitousek, a Stanford ecologist said in an interview, "There's a great danger in doing something like, oh, overfertilizing a cornfield to boost biofuel consumption, where the carbon benefits are far outweighed by the nitrogen damage." But farmers aside, this speaks to a more difficult issue for individuals who choose to seriously consider climate change.
The nitrogen issue illustrates that there's much more to global warming than immediately meets the eye. According to The New York Times, the greenhouse output of nitrogen "is about 17,000 times more potent than carbon dioxide. Its estimated worldwide release into the atmosphere this year is equivalent to the total global-warming emissions from Austria." Until recently, nitrogen was not a trendy buzzword of the environmentally conscious.
With such an enormous impact, it's surprising that the "nitrogen footprint" has not become more of an eco-Cause célèbre. But beyond measuring the size of our nitrogen impact--or our carbon impact--we must look at the bigger picture of climate change. Ultimately the threat of nitrogen as a greenhouse gas should make us aware of the nuances of our evolving atmosphere and the ever-unfolding dialogue between our behavior and elemental and atmospheric reactions. Whether or not we understand (or foresee) the scientific details of global warming, we can understand and become accountable for the actions that cause climate change on a local level.
The issues may not be in our backyards per se, but the pollutions of our rivers, the smog over our cities and the farming techniques championed by the growers who put food on our tables are all much closer than the Gaseous Atmospheric Nitrogen Store. We know what to do about these issues, even if we've yet to fully comprehend the interplay between the greenhouse gasses we've created. The revelation that climate change is more complex than we first understood should not make us feel defeated or alienated from the issue: instead, it should reinforce how simple the solutions and prevention can be.