I think if there is an effort made (which there will probably have to be), it'll be something cheap and dirty, like stratospheric aerosol injection.
This might be violent (everybody kills their neighbors, reducing the population and hence greenhouse emissions), or it might be economic (as fossil fuel prices rise, renewables become increasingly price-competitive, such that some people end up making a lot of money electrifying the world). Personally I'm rooting for the economic solution.
An impossibility because so called 'economic growth' (which is no more than global entropy increase) is coming to an end as degraded ecosystems worldwide fall into collapse. Climate change is only the most salient of literally thousands of distributed causes of this, but the overview is: the physical loans taken out on our global systems over the past two centuries are coming to maturity. It's payback time.
In the meanwhile, you have most nations around the world living and making progress peacefully. Nations that can be easily convinced by some form of aid or assistance to get on the bandwagon.
Don't be fooled by the news media. Most peoples of the world just want to live and let live. However, if the leadership of the US continues to be dominated by anti-science racist right-wingers, I am sorry to say, this won't happen. That is probably the biggest threat to any progress, not inter-government cooperation.
don't really know what race has to do with it, but big international banks are a bigger threat since they won't let any nation unplug from the global economy. follow the money.