Well, not to get all Malthusian or anything, but I think population is the major issue. We have two countervailing forces:
- "Economic Growth" as currently defined basically demands population growth. Even with geometrically increasing productivity (driven of course by all that free energy!), we need more bodies for economies to grow, and without growth, we run into severe dislocations of people and resources resulting in inflation and recession.
- Population outstripping resources (even if its just in the short term for you radical free-marketeers who think there are no limits), makes this necessary growth at least painful if not in the long term unsustainable without major changes in lifestyle (those Malibu luxury homes will be 500 story condos and there will be 5 minute rotations on the beach blankets and wave reservations for the surfer dudes).
We're still growing our population at geometric rates world wide, and even with free energy, I see having 12 billion bodies, most of whom are poor and disenfranchised as a huge political as well as resource allocation problem that will make the oil crunch look like a tea party.
How do we dramatically slow birthrates in the third world when life there is so entirely dependent upon manual labor and popping out as many kids as possible is the only survival tactic? How do we fix that one?
We all worry about the population explosion, but we don't worry about it at the right time,

Buffy