The US produces much more economic output per ton of CO2 created than China. Carbon efficiency of economic output is a key metric that we should be optimizing for. This allows us to grow the economy on a per capita basis while still reducing absolute carbon emissions.

"Economic output per ton of CO2" looks like a red herring to me. To borrow a phrase from elsewhere in this thread, the climate doesn't care about economic output.

I'm not saying we won't see costs from decarbonising. We will. I'm saying that worrying too much about the economics will significantly impede the necessary work (as it has done for the past 50 years). It's quite likely that the current financial system is the wrong tool for the job in fixing this problem, now.

The problem is, this CO2 difference is mostly because China has only 1/4 the per capita income of the US, and that income gap is rapidly closing.

So if China splits in to West China and East China, each can emit twice as much CO2?

China is more or less a single political body. If you're talking about large scale political coordination to prevent climate events, then it makes sense to focus on the largest autonomous contributor

This is a coordination problem.

A problem in which everyone is supposed to suffer a little to prevent greater collective suffering in the future.

It has one important characteristic: everyone would rather not suffer and let some else suffer. When problems are like that, there is need for coordination, for people to agree on what is a fair amount of suffering for each actor.

I happen to agree that CO2 per capita is a much better measure of what is fair, especially when comparing the US and China, both countries that are growing very little in population

Another important characteristic is that one tribe has already enjoyed (and continues to enjoy) significant quality of life enhancements due to much higher consumption of fossil fuel per capita.

Politically, you’re simply not going to get anywhere with asking everyone to suffer “a little”.

Also, the whole detached single family house with 2 car garage on quarter acre lot has to go, but Americans are not going to give it up, and other countries’ people aspiring for it are certainly not going to give it up.

Yep...

Those comments about some economies going carbon negative are making more sense when you see it as a coordination problem with the fairness issue.

Its like, China should grow its carbon consumption by no more than X, and we will go 0 and capture. That is quite possibly a fair way, and still cooperation from all the parties