Every one square kilometre of urbanized land requires 10 sq. kms of forest in continuous production to supply the wood fibre and paper, 50 sq. kms of arable land to produce food and 133 sq. kms of marine waters to produce fish for every 1 sq. kms of urbanized land.
And it gets worse. Look at the blocks on the right. “Everything that goes into the economy comes out as waste that must be assimilated.” (The black represents conservative estimates the right “a bit wangy.”)
From a talk by one of Canada’s most eminent environmental scientists, William E. Rees: The Vulnerability and Resilience of Cities.