Energy is effectively infinite, but not at a rate that's going to effectively substitute for the 160 exajoules per year currently provided by hydrocarbon energy. While I'm a big fan or renewables, even with a full-on effort at conversion, you're just not going to be able to sustain an interdependent, international supply chain based on *cheap* energy, nor will you feed 7 billion+ humans.
Fortunately we don't have to. When was the last time you bought gasoline for 17 cents a gallon? Probably never in your lifetime. Ok, so the nominal price that was prevalent for nearly 60 years is misleading. When was the last time you bought gasoline for $1.50 a gallon, inflation-adjusted? Some time in 2000. The inflation-adjusted price is double that now, and never in history has it been cheaper, before or since.
People talk a lot about Peak Oil. That was probably it. The price is going up again, so we're already past operating our interdependent, international supply chain on cheapest energy. You could reasonably argue that we're still operating it on cheap energy, but even after doubling the price, we're still running civilization. To judge by most of the rest of the world, we can double it again and we'll still have something that looks very much like our current civilization. Are you going to argue that energy that costs four times as much as it used to cost is still "cheap"? How about 8 times? 16 times? We're going to find out, probably in our lifetimes.
A big fan of renewables you may be, but you haven't really grasped the numbers yet. 160 exajoules annually sounds like a lot, until you see exactly how much power the Sun delivers annually. 3,850,000 exajoules. Year in and year out, that's how much energy we get from the Sun. Or in other words, enough energy to run our civilization for a year is delivered every hour. Hour after hour after hour. The delivery rate is vastly in excess of what we need. We only have to figure out how to capture a tiny fraction of the total available energy every hour to not only sustain our current interdependent, international supply chain, but continue to expand it as well.
The coming population bottleneck can't be avoided. We will, as a species, one day exist on sustainable energy - all of the remaining 300 to 500 million of us, if we're lucky, and we don't throw too many nukes around to celebrate the transition.
Sure it can, and I just showed you how. No one knows what the peak human population will be, but I'm betting it's considerably higher than 500 million. Given the sheer availability of solar energy, I'm betting peak human population on Earth will be considerably higher than 7 billion, and there will be no major population bottleneck induced by economic disruption. The price of hydrocarbon energy will trend upwards, while the price of solar energy trends downward, and the two curves will intersect, then reverse positions. Solar, in its various forms, will pick up where the hydrocarbons left off. There have never been more engineers on Earth than here are right now. Do you really think we're sitting around doing nothing?
Nothing short of a major comet impact is going to induce that population bottleneck, and with just a little more time the engineers of the world will be able to prevent that too.
So relax and learn to love the bomb.