The lessons nitrogen teaches

Yasmin Jayathirtha

Last month, we considered the biogeochemical cycle of nitrogen and looked at the impact of human activities on it. I have just read an interesting article, in New Scientist, about a nitrogen footprint calculator. We have read a lot about our carbon footprint but why nitrogen?

In this article, Allison Leach, an environmental scientist, who was involved in the development of the nitrogen calculator, says, in response to the question –

“But isn’t nitrogen just a naturally occurring gas? Why worry about that?”

“For the footprint, we are concerned with reactive nitrogen; everything except the unreactive nitrogen gas (N2) that makes up about 80% 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. It is a bit of a dilemma because we need nitrogen to survive – we consume it as protein – but when it is released in the environment it causes these problems.” The nitrogen footprint itself can be calculated online at and is about resource use.

The author works with Centre for Learning, Bengaluru. She can be reached at

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