Science

Published on September 19th, 2008 | by jessicajensen

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Low Impact Living: What’s Your Nitrogen Footprint?

footprint in the sandIt seems these days that you can’t get away from reading about carbon anywhere. From supermarket shelves to rental car counters, carbon labels and carbon offset offers are showing up everywhere. Part of this is because of the importance of and growing concern about global warming. But there’s another good reason: it’s a great single currency with which to compare the energy use and environmental impacts of very different kinds of activities and products. Pre-carbon, you had to use units like British thermal units (BTUs) or joules to compare the relative impacts of using gasoline to electricity or natural gas to fuel oil. Even then the calculations could be difficult and the results not very tangible to those of us who aren’t chemists. Carbon content makes it much easier. We can all envision carbon dioxide gas coming out of our tailpipes and smokestacks, so it’s tangible. And a carbon estimate allows you to quickly compare the relative environmental impacts of different product choices.

There is a price with this growing success, though: if you can’t measure the impact of something with carbon, then it can lose out in the court of public opinion. The environmental impacts of some items that are low (or unmeasurable) in carbon but high on other dimensions (water use, stormwater runoff production, etc) are often minimized. An increase in biofuels, for instance, might reduce the carbon content of motor fuels. But what if the biofuels are grown with intense nitrogen fertilizers that double the size of the summer dead zone in the Gulf of Mexico? Of what if we build 50 new nuclear power plants only to find that they exhaust regional supplies of fresh water for their cooling towers?

Water use / content is is one good summary metric: it could be a companion to organic labeling that might get more people to think about not just what is in their food but also how it is grown. Local organic rice could be great, but what if it’s grown in an arid area with limited fresh water supplies?

Another possible consumer metric that is gaining attention is nitrogen. Like carbon dioxide, various forms of nitrogen are required or produced by all living things and are pervasive in our environment. Also like carbon dioxide, excess nitrogen can have devastating and widespread effects. Nitrogen can produce acid rain and smog. Excess nitrogen in our rivers, streams and oceans can produce huge dead zones and/or algae blooms. Those gross algae blooms that almost scuttled the Olympic sailing competitions off of China? Fueled by excess nitrogen from fertilizer.

Richard Morgan of the New York Times recently wrote about the problems with nitrogen and the growing efforts to quantify it, including a project to develop a nitrogen footprint calculator. In the same article he also mentioned the concerns of environmental groups and leaders that a new metric like nitrogen could dilute our focus on carbon.

We don’t believe these concerns are justified. How many of us are able to digest the nutrition information on the back of a cereal box, or the list of vitamins in a smoothie or on a supplement label? We’re all starting to figure out what number plastic can be recycled and where, right? We can handle complexity, especially when “complex” means three or four numbers!

We also believe that better environmental impact information and labeling can’t come soon enough. Governments and businesses aren’t moving fast enough. At least right now, it’s up to us as consumers to figure out what products or services we will support by buying them. We just need the information to do it.

Image credit: ezioman at Flickr under a Creative Commons license



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