In reply both to Elven_Ranger and to Shadows Gallery: I agree, in principle; however, I think that if such a change occurs on the scale it is needed, there will be some physical over-flow effects.
However, I am rather skeptical of the time frame indicated (not to any study, necessarily, more to gut instinct), and frankly, if there is any real change that is going to occur, I believe that there needs to be a catalyst (of course, that's true for anything after all) and that people are more than likely going to need to be it.