It's Time to Consider Our Food's Nitrogen Footprint Too - Shrinking Ocean Dead Zones Depends On It

milk splash photo

photo: Tambako the Jaguar via flickr

We're pretty accustomed at this point, those of us in the green community at least, of talking about the carbon footprint of our food. But what about the nitrogen footprint? Considering that large effect nitrogen pollution has in creating ocean dead zones (and climate change will only make it worse), perhaps it's time we started taking note. New research from the University of Pittsburgh shows the way:Writing in the journal Environmental Science & Technology, Xiaobo Xue and Amy Landis examine which foods contribute most to ocean dead zones through nitrogen pollution (their eutrophication potential) and compared this with their carbon footprint, as established by previous studies.

Chemical & Engineering News sums it up:

Red meat topped both footprint lists, making it the food with the greatest impact on both climate change and eutrophication: Eating a pound of beef creates about 22 lb of greenhouse gases and about 2.5 oz of nitrogen pollution. Cereals and carbohydrates had the smallest footprints, with each pound of food releasing only 3 lb of greenhouse gases and almost no nitrogen pollution.

But many foods had diverging impacts on the climate and coastal ecosystems. Dairy products landed at the bottom of the carbon footprint list with carbohydrates, but sat second only to beef in eutrophication potential, releasing 1.1 oz of nitrogen pollution for every pound of food produced.

american average food consumption image

Bigger version of this image at Visual Economics

Emily Gertz notes in the article blockquoted above that though America's dairy and beef consumption produce roughly the same amount of greenhouse gases, the nitrogen footprint of all that dairy is about four times that of its beef consumption.

When you consider the average American diet (so wonderfully illustrated above) and all the dairy consumed, considering nitrogen footprint takes on new importance.

Here's the original report: Eutrophication Potential of Food Consumption Patterns
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More on Ocean Dead Zones:
Climate Change Causing Ocean Dead Zones to Grow
Crop Biodiversity a Cure for Ocean Dead Zones
A Primer on Global Warming-Caused Marine Dead Zones

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