For a discussion on this see: https://dothemath.ucsd.edu/2012/04/economist-meets-physicist/ https://dothemath.ucsd.edu/2012/04/economist-meets-physicist... Is

For a discussion on this see: https://dothemath.ucsd.edu/2012/04/economist-meets-physicist/ https://dothemath.ucsd.edu/2012/04/economist-meets-physicist... Isaac Asimov wrote a short story which touches on this (basically the last zookeeper/pet owner is confronted with the requirement that his ménagerie be exterminated) and also did some calculations --- if the earth's crust were converted to biomass, there would be a limiting element if memory serves, phosphorous.