Thorium, we have enough to safely satisfy our energy needs for over a hundred thousand years. We can even use those reactor designs to burn up spent fuel from our current bomb producing light water reactors. This just needs the investment and for the public to support the idea. Those designs are much much safer than current ones as the coolant used as a molten salt, so they run at a much much lower pressure. Thorium is also a way less prone to thermal runaway so in the case of a meltdown the bottom of the reactor would just melt and release the contents into a pit below to cool. Thorium is useless for building bombs. If we had any sense at all we'd have been encouraging Iran to build molten salt thorium reactors, they could take a world leading role in the field, create something truly groundbreaking and there would be no fear of bomb making
As it is we're treating them like a rouge state that's not allowed to have what we do, all that's ever going to do is get them to do it anyway just underground where we can't bomb them, it's ridiculous.
Also fusion, which again, we know is technically achievable, just no one has invested in it to the point of payback, brussard reactors have been build as small tests and have shown that they'd start paying back at a certain size then more and more as you scale. The US navy is funding a project right now to explore this but they're pretty secretive about it and from the sounds of it don't want to get any press until they've delivered a tangible product.
There are various other technologies which we know are feasible we've just not bothered to implement that could similarly solve the problem. Why we haven't is I guess a mix of politics, money and I imagine the pressure exerted by oil companies to maintain their own business.
I do think as a species we'll survive these things, the state we manage to though is entirely dependent on how long it takes us to get our **** together. I'd really much rather not watch the world suffer from famine, poverty and pollution before those that remain harness these forms of energy and re-engineer the world back into shape.
If I won the lottery, that I don't play, tomorrow I'd probably pour all but a hundred k or two into fusion research, there's a guy more or less crowd funding an experimental bussard reactor and he seems to be doing pretty well for himself. To make a full prototype that is marketable and a practical source of energy would cost about £400m, though then you could sell the designs all over the world.
