It's insane to talk about ending growth when we haven't even put down colonies in the sahara.

I'm hoping this is a joke?

It did remind me of an off-topic pet peeve - it's absurd to start thinking of a colony on Mars before colonizing the Sahara and the Antarctic, both being orders of magnitude easier and more useful than a colony on Mars.

Yeah. Until we've tiled the solar system with solar panels, fusion reactors, and people, we're not done with local growth. Of course, Earth's surface would be converted first, and you might want to treat that as an externality to be taxed and regulated (as we already do with national parks etc).

Giving up on our current system will kill billions during the chaos of the transition. Green New Deal is still Industrial Capitalism, which is one of the reasons why it's a great idea.

Green New Deal is a major step in the right direction, but it will not be enough by itself to stop global warming. It is the best way I have seen to start a smooth transition to a new economic system.

Unfortunately, there is no way to still have industrial Capitalism, even under a global Green New Deal, and reduce emissions enough for the world to not go through catastrophic global warming. If we do nothing, the transition will be catastrophic as you mention. If we try to start major reforms today, we might have a somewhat smooth transition. But there is no way to avoid the transition to something new.