I am wondering if there will really be a clever technical solution to climate change. Maybe we just need to come to terms with the fact that we have been living drastically above our means and we need to adjust our standard of living accordingly.
Take electric cars. If their greater efficiency makes them a green solution then the Watt steam engine's greater efficiency should have made it one of the greatest sustainability solutions of all time.
On the contrary, it's the poster child of the industrial revolution. Each use used less coal, but overall coal use went up. Increasing efficiency is orthogonal to lowering total waste.
Making a polluting system more efficient pollutes more efficiently. Everyone who isn't an economist can see the results of our world: more efficient than ever and creating more total waste than ever.
Changing a system's goals, say from growth to enjoying what we have and from externalizing costs to stewardship, will change its outcomes.