The fact that people have used industrial chemistry to short-circuit the nitrogen cycle, by making fertilisers out of nitrogen in the air at a rate which greatly exceeds what natural systems can manage, has real environmental effects.

ECONOMIST: The global environment

Eating meat is the dominant driver of the nitrogen cycle in Europe.

BBC: Nitrogen pollution 'costs EU up to ?280bn a year'

It points out, though, that there is little evidence things like the behaviour of the nitrogen cycle or the phosphate cycle in the Holocene were particularly well-suited to humans.

ECONOMIST: The global environment

And according to the Planetary Boundaries concept, the nitrogen cycle is already one of the places where humanity has already broken through the "safe limit".

BBC: Food: Organic growth?