We’ve all heard of the “carbon footprint,” and many of us—businesses and individuals—have begun to take a look at what our carbon footprint is and make changes accordingly in order to reduce it. But over at New Scientist, an environmental scientist talks about the hitherto unregarded nitrogen footprint.

It's the total amount of nitrogen you release per year. It is linked to various areas of resource consumption, with the biggest factor being food - what you eat, how much and how that food is produced. There is also an energy component, which includes transport, housing, goods and services. ... For the footprint, we are concerned with reactive nitrogen - everything except the unreactive nitrogen gas (N2) that makes up about 80 per cent of our atmosphere. All other forms of nitrogen are reactive in some way and can cascade through water, the atmosphere and the land to cause a series of environmental and human health impacts. They can contribute to smog, acid rain, biodiversity loss and many other major environmental problems.

So, just as there are various carbon calculators out there, now there is a nitrogen calculator that lets you see how various everyday activities contribute to one’s nitrogen poundage. The majority comes from food—but should one eat less to reduce one’s nitrogen footprint? Not necessarily, but eating sustainably is one way of doing so.

For example, choosing foods from farms that use nitrogen in a more sustainable way and reducing your utility usage will reduce your nitrogen footprint.

Furthermore, from the New Scientist article:

One simple change is to reduce food waste. In the US we throw away over a third of our food. That's like going to the grocery store, filling up three shopping carts with food then throwing away one of those. Cut that down and you cut your footprint. Another big aspect is the amount and type of food you consume. In the US we overconsume protein, about 70 per cent more than we need.

Many of the recommendations for reducing one’s nitrogen footprint are the same basic things that contribute to sustainable living in general: reducing energy consumption, eating better, reducing waste, etc., so whilst I am anal retentive enough to like keeping data on my various consumptions, it does seem a bit needlessly complicated, and at some point we may be encouraged to track our contribution of every element:

Are there other footprints that could get the same treatment? The big one is the water footprint. That is generally done on a national basis, but there is no reason why it could not be done on a personal basis. And perhaps phosphorus as well, because of its use in fertiliser.

Good grief, we’re going to end up with more footprints than an Arthur Murray dance studio! (Bit I bet Superman would have a pretty low krypton footprint.)