lol at the optimists, the entire global economy is built on fundamental growth of the population, its unquestionably not sustainable, that doesn't mean it will break down tomorrow but, there isn't an area on earth with enough space for unchecked population growth.
Look at China's growing power demands, power station building and polution increases, this will only INCREASE over time, not decrease, lack of food, more and more people living in poverty in the rich countries of the world.
The world economy is a ponzi scheme and I hope to christ it holds on till I get to a decent old age before it collapses.
We already have wars based solely on resource control, the problems will start when two bigger countries fight over a smaller country and their resources, or more accurately, when two of the bigger nations have no choice but to go after the same resources as someone else........... that or all the big nations will all at the same time decide power isn't worth it, population growth is a bad thing, being nice and having world peace is great and wasting power and creating polution has to stop.