It's entirely correct to think about the future, but it's an open question whether a person of the present time can think sensibly about problems 200 years in the future. It's a bit like 1890s urban planners worrying about the horse-manure crisis ( http://j.mp/bCo4sg ).

The way I see it: we could reduce our living standards and guarantee a crummy future for our descendants, or keep our living standards and trust that someone in the future will figure out how to make it all work, thus giving our descendants a shot at decent living standards.

The linked SciAm article nails the real problem though: energy density. Petroleum is simply a very good fuel. No other non-science fictional alternative comes close (Current battery technology sucks efficiency-wise so electricity isn't an answer for now.)

We need to spend much more on energy research, that's for sure. Manhattan Project-style programs won't work because there's no one true way to create sufficient amounts of clean energy. We desperately need people to try lots of different things -- perhaps the Silicon Valley VC model is better suited to this.

PS. There's an amazing chart over at the Oil Drum: http://www.theoildrum.com/files/world_primary_energy.png ... shows how little renewables like wind and solar are currently contributing.