This is nothing new: we have long known that positive feedback loops will accelerate the warming of the planet. First, the polar regions will warm most quickly

This is nothing new: we have long known that positive feedback loops will accelerate the warming of the planet. First, the polar regions will warm most quickly due to the earliest feedback loops: snow is reflective, heating removes snow, water/ground is much less reflective, more snow melts. Second, we will have more fires (huge GHG emitters), more water vapor (the #1 GHG by far), and more methane emissions from natural sources which are exposed due to snow melt. I don't see much way around this: we're going to have to alter our atmosphere even further if we want a habitable planet. We're both going to need to stop altering it by emitting far less GHG, then emit other compounds like aerosolized sulfates which reflect sunlight, then we'll need to pull out CO2 from the air to deal with the ocean acidification and restore the proper amount of carbon in the air.