The average rates at which people consume resources like oil and metals, and produce wastes like plastics and greenhouse gases, are about 32 times higher in North America, Western Europe, Japan and Australia than they are in the developing world. That factor of 32 has big consequences.
I suspect you heard that one before, no!? Well, Jared Diamond also makes this obvious consideration:
People in the third world are aware of this difference in per capita consumption, although most of them couldn't specify that it's by a factor of 32. When they believe their chances of catching up to be hopeless, they sometimes get frustrated and angry, and some become terrorists, or tolerate or support terrorists. Since Sept. 11, 2001, it has become clear that the oceans that once protected the United States no longer do so. There will be more terrorist attacks against us and Europe, and perhaps against Japan and Australia, as long as that factorial difference of 32 in consumption rates persists.
(My emphasis in quote.)
Controversial professor? Or just stating the obvious? (I say: stating the blaringly obvious!)
Jared Diamond recently vented similar thoughts in an interview: Population versus Consumption (transcript and audio).