But the world is a complicated thing and we’ve got >7 billion people to feed!

Yes, and capitalism works to deny those people as much food as possible, to give it to others who can pay more. If you buy groceries and literally throw them away, that's better for the companies selling the food than you using it. We've known for 50 years that climate crisis was coming, but in order for capitalism to keep expanding, they kept pouring (literal) fuel onto the fire.

I think we should be very careful before deciding “yeah it’s time to tear down the existing systems and hope that there are better systems out there”. It’s easier to make things worse than to make things better.

Worse for whom? We're literally looking at unlivable temperatures popping up all over the globe, not to mention the storms, land erosion, lack of water, and the fact that soon, we won't even be able to grow food like we do now. You think we'll have cattle farms in 50c heat?

We don't need a new system, we have one: Socialism. Not communism, socialism. Governments should exist to enrich and help their people, not to enrich a tiny percentage of them at the expense of everyone else.

Capitalism is about exponential growth, on a planet with finite resources. Eventually, you get to where we are now: End Stage Capitalism. A tiny number of people have a bulk of the wealth of the world. The game is over, they won. They made the planet unlivable for humans in a few generations in order to do it, but they won. Congratulations (confetti)