"Well over half of the Greenland ice sheet appears to have melted to bedrock in the not-too-distant past [when humans did not yet exist], when temperatures weren’t much warmer than they are today"

Does that make you feel good? I guess if you're in the sandbag business or have a lot of high elevation property...

Maybe? If it melted before and the climate recovered to its non-warm cold state, what ever mechanism activated before may activate again.

Who cares if the earth cools down 100000 years after the ice caps melt.

People who differentiate between the end of the world and the end of humanity on the world.

There are two philosophical approaches to climate change, one is to ignore it and die, and one is to accept the change and plan around it.

"Ignore it" in this case means operate under the misperception that humans have the ability to control planetary climate (effect it sure, but control is elusive).

If you're in the build your way out of it mode you can be confident that over the millenia there will be times when it is easy to walk around, and times when that is hard. If you're in the ignore it camp you can be confident that the new species that emerge after humans are gone will also have large periods where the climate the evolved to is present before it changes again.

You you see? Hopeful, the world will continue with us or without us.

No, worse :(

We thought that it was harder to melt Greenland's ice.

But time will tell ;)

Edit: Better, maybe, if you're speculating in Watchung Ridge beach-front property ;)