There are a lot of thoughts here. Doomerism is obviously not productive. If it helps, antarctic sea ice is not what we should worry about - the southern hemisphere is relatively more stable due to less land and antarctica itself. The blue ocean event (no north pole sea ice) is the one you should worry about, probably late 2020s. Because once ice finishes melting the energy goes into increasing temperature instead of state change from ice to liquid. The good (dubious) news is, the global capitalist economy is much more fragile than it might seem. In my opinion, industrial civilization would collapse before we would surpass 4 C warming, which still leaves most of the planet as “habitable”. I believe economic growth will turn negative much past 2 C warming, thereby limiting subsequent warming. Because we’re warming the planet so fast, the system destabilizes at much lower temperatures than we have on the fossil record. At the risk of being sanguine (ok yeah this whole post is sanguine), it’s kind of nice that the heat accumulating at the ocean surface will not have time to interact much with deep, cool ocean water. So we’ll wind up feeling much more heat in the short-term than we’d feel in the long-term, which could spur humanity to actually do something. Overall, communists should feel optimism in the face of economies running up against planetary boundaries. Humanity’s survival depends on global cooperation. Replacing capitalism with socialism would be a (the only?) feasible way to achieve this. We’re already seeing beastly temperatures and extreme weather worldwide. I would bet that the children being born today will see these horrific weather events and start movements that will make Extinction Rebellion and Just Stop Oil look like tea parties. If we don’t blow ourselves up in the next 30 years then, I’m fairly optimistic. But perhaps I underestimate the ability of capitalism to assimilate young minds