The melting arctic ice sheets cause an influx in cold freshwater in the north atlantic which works to slow the rate of thermohaline circulation, which is responsible for bringing warm sea water (energy) to the poles which accelerates melting. It's a big unknown what exactly will happen, but it's possible that the damages of climate change are less than projected if the thermohaline circulation slows sufficiently to bail out the world until it can start reducing carbon emissions cost effectively.