I don't think they ever have...
>
>Could you ask Summers if Africa is still vastly underpolluted?
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>Doug
Well, don't you think it is? Wouldn't you be very happy if African air had more sulphur dioxide in it, and Africa were a richer place? The question is: "how much of one, and how much of the other?"
Personally, I think that developing countries poorer than Mexico is today should have *no* obligations to control their emissions of, say, greenhouse gases for the next fifty years. What is to be done ought to be done, as a matter of simple justice, by the industrial core.
On the other hand, I would be unhappy (and you would be unhappy) if there were more oil pollution in the Niger delta, and nothing in exchange but fatter first-world bank accounts for Nigerian generals...
Brad DeLong