The goal is to not sit on or arses while we wait for people who already produce less CO2 than us to reduce their usage.

The real measure should be CO2 output per unit of GDP. We still need to make stuff, so if you're going to release CO2, it better be an efficient use of it.

That's convenient.

Presumably you'll stop driving, give up home air con and electricity, never fly anywhere, etc. Because those things aren't related to your GDP production.

Disagree. All of those contribute to GDP. Someone has to make gas for my car, electricity for my air con, build a jet, etc.

That seems like it could be gamed:

http://www.smbc-comics.com/comic/2013-01-14

We're already making a lot more stuff than what is needed (consider half of food is thrown away as food waste). What economies are fighting each other about these days is not so much availability of resources, as being the one who gets to make and sell in order to produce income.

Morally, it matters who makes things. The countries with high GDP who are responsible for the current extra CO2 in the atmosphere could always (you know, in theoretical fantasy-land) help out to make sure others produce as efficiently but reap the benefits. Instead of using the argument you make to pull up the living-standard ladder behind them.