In a worst-case scenario, there will be severe economic dislocations and political turmoil, and undoubtedly some conflict, although how much will depend on the severity and rapidity at which the crisis unfolds and how much the international community will be willing to cooperate.

I don't have the gloomy outlook you do. If the worst happens (which is still not a sure thing)I think we'll get through it with a little luck; human beings are adaptable, and sometimes they have been able to rise to the occasion. But I do believe the world population will drop precipitously and standards of living will fall to 19th century levels.

My guess is the world leaders which will emerge after such a crisis will be countries with a developing industrial base but with plenty of people still in the countryside who can grow their own food, make their own clothes and build their own houses with a minimum of technology.

I'm betting on India and China, and maybe Brazil.