It's going to take us a hell of a lot longer than 20 years to move the entire economy to wind and solar (including transportation). You're probably right that were fucked anyway but I for one don't think we should bet the entire civilisation on an unproven technology. As in no other country has managed to go purely wind and solar.

There are countries with up to 80% of all electricity generation from nuclear, which has almost the same levels of carbon emissions as wind but with fewer deaths. Put it this way. If every country had the nuclear mix that France has, we'd be halfway there with dealing with the climate crisis.

I blame organisations like the greens and their fear mongering for us not going nuclear so there's no better time than right now to start the journey because the last thing we want is to rely on wind and solar and then if it doesn't work, have to start down the nuclear path another decade from now.