It seems to me that you are not at all interested in a real solution to the problem. For you, the solution is already clear: everyone has to make their contribution, no matter how big or small.
The interesting thing is that your solution is not problem-driven, but purely ideological. Whether the solution can be implemented practicably, from my point of view doesn't seem to be any interest to you - as long as all subordinate themselves to some kind of strange socialist maxim, in which not the individual counts but only the people (in this case a kind of state union).
Because a problem-oriented approach for a solution would be to look at the number of political systems and what part of the CO2 budget they control. It makes a fundamental difference to implement effects in 20 different systems or in one. Because time matters. And therefore efficiency. So why waste time on Iceland if China plays a much more fundamental role in the issue.
So if China were divided into 20 political systems - states - the situation would be different. But it isn't. Again, it seems to me that you don't care about the structure of the problem as long as everyone follows the given morality plan.
And to answer your question - the first and only interest of an Indian rice farmer is to care about it's family. To fight starvation. And maybe that his or her children may have a better life than being an Indian rice farmer - so they spend their money rather on school education than having a single thought on global warming.
The same is roughly true for China. China's first interest is prosperity for its citizens. You don't stand at the head of such a country without looking at the needs of your own people.
Your whole solution is already going against the very nature of man: to be an egoist driven by instincts.
Do you really believe that the goals will be achieved worldwide? What if someone resists to join in? Do you then want to enforce these goals with weapons?
What I would really like to know is: Do you seriously believe that in the next 5-10 years humanity will overcome its differences and together put its economic interests aside to achieve the goal? And all this without the greatest social riots ever seen?
So do you really see a realistic possibility that the problem is solved in the next 10 years? And what happens if not?
