The people who will be the most affected by climate change will be the folks living decades if not centuries from now. And those people will be, on average, orders of magnitude more wealthy than the people of Earth today.
This is even more striking when you consider that the major contributor to greenhouse gas emissions over the 21st century will not be from the wealthy folks living in the current G8 countries but from what are now developing countries (China, Indonesia, India, Nigeria, Brazil, etc.)
The moral calculus becomes a hell of a lot more complex when you take this into account. In 50 years the people of Bangladesh are likely to have developed world levels of per capita GDP, and by 2100 they are likely to be richer than Americans living today. Does it make sense to hold back the current development of not just the US but also places such as Bangladesh and China in order to benefit the incredibly wealthy citizens of the future Earth? Moreover, the case for severity of damages to the future Earth due to man made climate change are rather weak. The current best estimate of sea level rise by the year 2100 is rather moderate, much less than a meter and at present being revised downward due to more accurate estimates. Does it make sense to spend even billions of dollars today to save a future world that will have a global world product of literally quadrillions of dollars (adjusted for inflation)? And will have vastly more advanced technology than we do today?
As to what will happen next, I think the people of the future who will have the benefit of: vastly greater wealth, vastly more advanced technology, and hopefully much more accurate climate models borne out by being able to compare models against nearly two centuries of data. And for those reasons they will be unimaginably more capable of both figuring out what changes would be warranted as well as having the ability and wealth to make such changes without incurring a huge amount of personal misery.