In his September 11, 2013 Times of India article (reproduced on Yale Global) "A Syrian Lesson for India" Nayan Chanda traces the origins of the current civil war in Syria to multi-year draught that generated a large migration of from the affected areas to Syrian cities. India (and many other countries) are so close to the environmental "edge" that even the historically natural variations in climate are almost certain to put the socio-political-economic system under unbearable stress in not very distant future. Since any discussion of population is politically incorrect, I am not even sure what else India (or Pakistan or Bangladesh for that matter) can do to ameliorate this risk. Interestingly, an article by Ellis in September 13, 2013 New York Times is titled "Overpopulation is not the problem."

Of course, I would like to share Ellis's optimism, and think that at no stage of our existence shall we become bacteria in a petri dish. The critical statements in that article are

1. "Who knows what will be possible with the technologies of the future?"
2. "Our planet's human-carrying capacity emerges from the capabilities of our social systems and our technologies more than from any environmental limits."

The first is a statement on uncertainty about the future "our ignorance presented as knowledge in a rhetorical form. I also hope that our ingenuity in devising social and technological solutions to our challenges will keep up with the population for ever. Unfortunately, history of rise and fall of human civilizations and their populations (Rome, Mesoamerica, etc.) does not encourage such optimism.

Second, co-determination of the human-carrying capacity by social, technological and environmental considerations does not mean that the last factor is irrelevant. He has not made a case that joint consideration of factors A, B, and C should lead us to drop C from the equation.

Several consecutive draughts in Syria did not enable the population to devise technological solutions to food shortage in short order. The social response was migration and war. What happens if the monsoons fail in India for two or three years in a row. Will the densely populated deltas of south and southeast Asia be able to find the "social and technological" solutions to the sea levels rising by 10-20 feet over the next century?

Perhaps Mr. Ellis's answer is yes. Neither the "sky is falling" environmentalism nor Panglossian  consumerism are unsustainable.