One can imagine all sorts of dystopian futures. Here's a much more realistic one: the climate goes to hell and there is war, famine, and mass extinction. Democratic governments are replaced with authoritarian governments in elections because populaces want protection from their neighbors and are willing to sacrifice their autonomy to someone who promises to shoot their enemies. International cooperation breaks down.

Imagining the world not doing anything about climate change is a lot easier than imagining them doing too much. We can already see the former.