I'm sorry, is the ice melt actually accelerating because of GW, or does it only seem that way because as the ice sheet has been getting smaller for 1000s of years, the rate of acceleration increased because the smaller the ice, the more heat it absorbs. A larger piece of ice has a massive volume packed behind a smaller proportional surface area. It needs a lot more heat energy to change from solid to liquid, which takes more time. As it gets smaller, that accelerates.