The book addressed that area of thought much more in detail, but for starters the problem was more directly observable and promised near total extinction within a single lifetime.

Secondly, humanity didn't come together in a kumbaya moment, many had to be forced to comply. The woman in charge of Hail Mary project was a monster who nuked antarctica and was sent to prison when it was all over.

and then we re-elect them.. Green vote in Germany's recent election down 2.4%, AfD up 8%.

Now the Greens are a bit too liberal (by necessity, or they be even more ignored then they are now) but the path to any level of sanity lies through them being able to move the Overton Window to the truly radical politicians we need.

however, it's very possible we've already passed the point of no return, certainly by 2030-2035 we will have if we continue, as too many tipping points will be crossed to find a way back to a stable biosphere for millennia.