Interestingly, the IPCC reports themselves (not the summaries for policymakers) are quite optimistic. IIRC something like, if we do nothing to abate emissions, climate damages in 2100 will cause damage equivalent to ~3% of GDP per year. (With GDP being many times higher than now per capita). Hardly a catastrophic prediction!

I know, right? They bend over backwards to not be "alarmist," even perhaps a bit more than they should. But of course this wins them zero credit from their political opponents, which is an important lesson about politics: seeking middle ground with someone bent on destroying you is a fool's errand.