Now you're moving the goal posts from "the evidence shows X" to "what does it matter?"
For this purpose let's take as a given that the warming WILL flood the coastlines, costing $trillions to mitigate over time. The agenda is to put a cost on burning carbon which contributes to that predictable impact - such as a carbon tax. The point is for those of us who are using fossil fuels to pay the full cost of burning those fuels instead of offloading those costs onto the next generations. That is no more "anti-capitalist" than are clean air or water provisions that force polluters to pay the cost of cleaning up their waste instead of dumping their toxic waste onto your front yard or in your water supply, or killing you and your kin with dirty air, like is happening in China - 500k per year or more.
But more generally, the options to deal with AGW are incredibly complex to analyze. We might as society say, "Fk the next generation - we are selfish, and we want cheap energy today, we don't KNOW the costs will be significant, there's a small chance for the U.S. there will be benefits - growing oranges in New York! - and costs and the net is unknown, so to hell with the kids and grandkids - if they have to pay for our energy choices, so sad, too bad. OK, but we can't have an informed debate if we pretend the warming isn't happening or that our fuel choices are not a significant cause. Once we accept that our activities ARE warming the planet, THEN we can have the necessary and very difficult public debate about what to do about that.
