China and the US are the world's largest carbon dioxide producers. The 28 nations of the EU combined produce somewhat less than the US and a good deal more than India, the third place nation. China has at least promised to reduce carbon emissions, as has the US. India, despite it's rather small total emissions, is an interesting case since it has ambitious plans to double its coal production and because its plans for reducing emissions is even more committed to magical realism than the plans of the US and China. India and other developing countries argue somewhat reasonably that they should not have to bear the full price of cleaning up emissions since they played such a small role in creating the problem to date. They argue that they are consequently owed reparations.
The history of reparations suggests that this is a poor strategy. Reparations are nearly invariably payed by losers to the winners, and that's pretty much regardless of any abstract notion of justice. Moreover, they are usually a bad idea. the reparations imposed on Germany after the First World War played a big part in causing the Second.
I would bet that no poor country is ever going to collect much of anything from the rich in the form of reparations.
On the other hand, rich countries are likely to suffer nearly as much from climate change as the poor countries, so it makes sense from the standpoint of self-interest for them to help India and similarly positioned smaller nations adopt low carbon technologies. Enlightened self-interest is much more appealing than reparations.