HERE is a salutary tale about the World Bank. The first draft of its 1992 World Development Report, dedicated to sustainable development, contained a diagram labelled “the relation of the economy to the environment”. It showed a rectangle labelled “economy”, with an arrow entering it labelled “inputs” and an arrow exiting it labelled “outputs”. That was it.

It was my job, as senior economist in the bank’s environment department, to review the draft and offer suggestions. I said drawing such a picture was a great idea, but it really had to include the environment. As drawn, the economy was …