I don't think any of it matters, seriously. In 50 to 100 years, unless something truly miraculous happens, humanity it going to be in a world of trouble. Coal is going to be increasingly relied on, which is going to dump toxins into the environment (heavy metals into open water, filthy air causing lung diseases). Nuclear power is dangerous on so many levels (anybody have any idea how much radiation was dumped into the environment after the tsunami in Japan? Nevermind the problem of the waste and particularly losing the stuff or having extremists steal it). Meanwhile, oil is finite but demand increases, it's going to run out eventually, that's a fact, just like drinking water. Many people WILL be drinking converted sewage in the future
Converting Domestic Sewage Into Drinking Water M.I.C. Gadget Combine those two facts with continued increasing population and the outlook is grim, particularly for America. This country was not designed to support the European type gas and oil prices that are inevitable.
If the world leaders don't get their collective shit together and start cooperating at a global level, looking at the big picture and the future success of the species as a whole, things are going to get very, very ugly in a few decades.