There as a discussion that apparently got deleted about the feasibility of permaculture feeding the world, and I wanted to add something constructive to it. According to what I can find, it seems people suggest we may be running out of oil within 30-100 years - the key to our success as modern civilization will soon be gone - the major input to our food production may no longer be available. However, I posit that within 30 years, alternative energy, especially with the real pressure dwindling oil supplies (I wouldn't call what we have now pressure from dwindling anything), will advance to the point that it becomes feasible to replace fossil fuels as the major source of power for mechanical inputs to big ag based systems to the point that we may never see that big crash some people are predicting.
I've seen on here where someone calculated the overall energy inputs required to manufacture things in general and it seemed to totally disregard the fact that a solar panel could conceivably generate much more engery over time than what it took to create it, giving us a net gain in energy.
That's describing the exact opposite of what I suggested might happen. My premise is based on the fact that we will eventually have limited supplies of oil, but it won't be immediately, so as the cost of gas rises, you'll see people more readily purchasing, say, electric vehicles, and converting their homes to solar power where possible and this point will happen sufficiently far enough into the future that these alternative energy sources, mostly solar, will be quite cheap and already pervasive and at the same time much more efficient at converting solar energy than what we have today.