I'm going to be bias. I say that the US will still be a superpower, still fighting more wars, which from a result, deadlier and far more advanced weapons will be developed and I think the US will end their moratorium on experimenting with nuclear weapons. The environment as we know it will differ among areas, such as in China, it will be so bad because as a growning nation, they will guzzle up so much on gas and the emissions will make living in the packed cities of China, not eco-friendly or human-sustainable. I believe that fuel cell technology will solve the energy problem.
(yes, I realize I sound pyschotic, but that's what instantly hit me.)