This is a very difficult thread for me, because you’ve immediately started it from what feels like an insincere position of insisting on the polite debate of a system that has actively harmed innumerable people. And continues to do so.

While I don’t deny that polite debate is preferable to flame wars and anger, you’ve come in here to try and debate a subject that raises passions.

And the reason I say this from the outset is because of comments like this;

Environmental devastation is an externality because the rules haven't been defined properly-- if the rules of capital ownership around environmental concerns were clarified (through some system of carbon emission limitations and carbon credits), then I'm sure capitalism could optimize for a good environmental outcome. A bad thing, to be sure, but not the fault of capitalism.

The ‘rules’ in this case have been defined. Most countries have rules in place to govern the environmental impact of industry. But companies led by capitalists ignore those rules as far as they can, which is how we are where we are.

Here in the UK, we have record breaking amounts of sewage and pollution in our rivers, because our water companies are run by capitalists to turn a profit. The fines from the government are ultimately paid by those of us who pay our water bills. The people in charge continue to pay themselves and their shareholders well.

And this is where capitalism fails miserably, in my opinion. As noted in another comment in here: capitalism is built for profits, not for human comfort. Businesses who pollute know full well that they should reduce their emissions, clean up their waste, and be better global citizens, but left unchecked, they won’t. You admit yourself in that quoted comment, that capitalism needs a set of rules around carbon credits and such to address the problem. They know there’s a problem, but are waiting for governments to force them to clean up their act.

That doesn’t make me feel that capitalism is the kind, loving economic system we all need. Quite the opposite.