That little figure happens to be kinda important. In fact, I'll go out on a limb and state that most people consider their quality of life to be somewhat more important than abstract ideas about global economic policy.
"Fairness" had nothing to do with how we got here. Or, to flip it around, why would any country (let alone the ones the U.S. has abused for various reasons, artificially retarding their growth) agree to a model that dooms their citizens to a pre-industrial life?
This is no different than the arguments for flat taxes because progressive income tax is "unfair".
If you approach this sort of global negotiation with a precondition that it not alter the existing economic order, that is the same as refusing to negotiate. If that's your view, then fine; there's clearly no point in discussing further.
But if the goal is to deal honestly with climate change, the reality is that there will be winners and losers. Just like happened in the run-up to where we are now. Guess what: we won the run up. Now we have to decide if we're willing to give up some of the "unfair" share we've had for almost a century in return for our grandkids having something vaguely like the quality of life our parents had.
Some days I really think the U.S. is just doomed by our culture. Thankfully, I'm more chipper other days.