The vast majority of the "climate change" movement these days doesn't really involve climate change at all. Unfortunately for those legitimately concerned about the future of the planet, the left across the world has hijacked the issue of climate change to push an agenda (climate justice, socialism, etc.) that all but guarantees nothing will get done on the issue.
I've always fallen in the denier camp (and won't discuss why in this thread), but I'm also an engineer, so it's my job to develop solutions to problems. The goal of a solution isn't to make things worse, it's to fix a problem. I have seen very few proposals that wouldn't make things worse. Going to "100% renewable energy" isn't possible given current technologies, and every place on earth that has significantly increased their share of wind/solar has seen their electricity prices go up, as well as making the grids in those locations less stable.
If people see this is a "existential threat" and actually want to work to solve the problem, they'll drop all of the other crap they've attached to it and work strictly to lower GHG emissions. It'd be pretty easy to continue lowering emissions in the US without completely destroying the grid with wind/solar. Make short-term incentives for companies to convert existing coal power plants to gas power. That alone will allow for a nice drop in CO2 output, especially if carbon-capture technology improves any over that time. Don't shut down any existing nuclear power plants (like Diablo Canyon in California), instead work to start building new nuclear power plants. If the technology is there (i'm not sure how far along it is), build the new 4th generation nuclear reactors. If it isn't, build 2nd/3rd generation plants while pouring money into research for 4th generation nuclear. If you want to sprinkle in some wind and solar that's fine, but it is most beneficial in small % (say 5-10% of the grid), so I wouldn't make it a massive part of the plan.
Of course, none of that addresses the rest of the world. You can do all that in the US and significantly reduce emissions, and China/India will be producing more than the US cut in 10-20 years. Which brings around the last point - perhaps it would be more beneficial if a significant portion of the funds that would go to fight climate change be diverted to adaptation as opposed to mitigation. You don't need the rest of the world on the same page to do that.