Scientists didn't get climate change wrong. Once modelling began in earnest, the results of the models were so extreme and alarming that scientists were ignored/silenced and only the milder scenarios were made visible to the general public.

Now evidence is making it impossible to pretend any longer that those mild scenarios are playing out. The opposite is happening, the most pessimistic models have turned out to still fall short of the mark due to the number of positive feedback loops involved in global warming.

Scientists didn't underestimate anything, they were told to shut the fuck up and stop inciting mass panic if they wanted to keep their jobs. The fact that mass panic might have been justified didn't cross the minds of the politicians involved.

Climate change is a hard, perhaps fatal, lesson that society cannot be governed by career politicians. Opinions don't matter, election cycles don't matter, personal beliefs don't matter, 'this will ruin the economy' doesn't matter. What matters is an existential threat has presented itself and the scientists best placed to address it have been suppressed by the political technically ignorant ruling class so that it can continue its existence unimpeded for just a little bit longer.