The West Antarctic Ice sheet is still flowing into the ocean, and accelerating. It's actually not even clear atmospheric warming is the ultimate cause. But it is clear that it's reached a literal tipping point. The glaciers have retreated past a point where the slope tips inland, and warm water is running down hill, melting the bottom. No amount of emissions reductions can stop it, we would need to pump heat away from the underside of the glaciers to slow it down.
https://en.wikipedia.org/wiki/File:West_Antarctic_Collapse.o...