Addressing climate change is nearly impossible.
Any solution, short of massive die-offs or a return to stone-age technology -- or both -- will involve some pretty high tech, like GMO crops, non-petroleum power generation, non-petroleum vehicles, new ways of making cement and steel, new ways of making fertilizer, new ways of raising food animals.
All of these require investment and an economy able to make the investment.
Which means raising the living standard of billions of people.
Which means increasing their carbon output while they develop.
Which means making climate warming that much worse, and fixing it that much harder.
In short, a massive die-off might be our best option. Bill mentions, dismissively and in passing, some methods of "geo-engineering" which would alter the environment without having to change our behavior or altering our carbon footprint: putting huge amounts of nano-particles in the atmosphere to block 1% of sunlight, essentially mimicking the global smoke particles that killed off the dinosaurs. Also what happened in the past couple of ice ages which were caused by volcanism on a broad scale. Or seeding clouds with salt particles to make them more reflective (what could go wrong there, I wonder?). I've heard about proposals for orbiting solar shields, to block sunlight (and maybe even generate power). But all such proposals are likely to result in unintended side effects, and could make things exponentially worse instead of better.
I'm glad I'm old. We're all wholly fucked.