They just want signatories on a reasonable-sounding treaty — which will later be expanded and abused like the Montreal Protocol.
The NYTimes reports:
No American president is going to agree to a deal that would shut down the fossil-fuel industry 15 years from now, of course, much less get such an agreement through Congress. So you can see why the Chinas and Brazils of the world would be nervous. They fear the rich countries will try to muscle them into accepting emission limits that doom their people to lasting poverty.
What was the compromise that finally broke the Stockholm deadlock?
The scientists had wanted to specify a carbon budget that gave the best chance of keeping temperatures at the 3.6 degree target or below. But many countries felt the question was related to risk — and that the issue of how much risk to take was political, not scientific. The American delegation suggested that the scientists lay out a range of probabilities for staying below the 3.6-degree target, not a single budget, and that is what they finally did.
The original budget is in there. But the adopted language gives countries the possibility of a much larger carbon pie, if they are willing to tolerate a greater risk of exceeding the temperature target.
It remains to be seen if the carbon cap will become a major negotiating point when climate diplomats convene for their next big meeting this November in Warsaw. At the very least, the scientists have created a new yardstick by which any future foot-dragging on climate can be measured.