I saw an article recently (here maybe?) that the world could switch to 100% green energy and make the investment back in 6 years. I haven't looked at the math behind it, and actually getting that many solar panels up is going to take some time too, but it really seems to me like this is the main thing we should all be focusing on right now. Because of high fossil energy prices, getting rid of Russian gas, and of course because of climate change. Three very big reasons to go all out on clean energy.