People living close to the ocean and in deserts face the most iminent threat from climate change, however it is not the responsibility of anyone else to help these people to move. Many may have to start all over, but they should move. Moreover, there is no way to combat climate change, it is going to happen and we need to change with it.
I think climate change is unavoidable regardless of the measure of obligation any country has. The fact that people are growing in numbers allover the world means that more resources will continue to be needed to support them and pollution will prevail eventually. If a country is well developed it does not mean its obligations will be sufficient enough to solve climate change.