The nut has a point, but his timing is uncertain. Look at the angst caused by the current oil price runup, and extrapolate to $500-1000/barrel oil, but when might that occur and stay at that level? Not today, and not tomorrow. There's still plenty of oil around so rapid price runups like the current one are probably more speculation bubble-driven (and subject to rapid correction when the market wises up) than supply-demand. Conspiracy theories are always entertaining too.

Global warming is self-correcting in the long run, assuming the cause is human, because we as a species will run out of the convenient means to cause it (cheap fossil fuels, especially oil) and experience something like the crash Kunstler talks about. Yes, we tripled (or more) the food and the population, but if you can't afford to fuel the tractor any more (or you have to grow 2 fields of soybeans to fuel it and a field of jojoba to lube it - and what about parts and tires and space for the actual food crop?) you're back to the olde days. Only the Amish will survive? If us boomers are lucky, it won't hit badly until we're gone, but I do think our kids probably and their kids certainly will have to deal with it. Not much we can do about it now - we had our fun while it lasted.

Of course, there will probably be more use of railroads in the medium term because they are easier to run on things other than oil (return of steam and electric locos?) than cars and trucks, and more efficient at using oil so more cost-effective when the short term price runups happen.