I saw the following comment there and thought it was funny in its deadpan style presentation.
So, is there any plausible case where the following is NOT going to happen during this century:
1. Rapidly warming arctic melts the sea ice.
2. Melting sea ice exposes more and more open ocean.
3. Open ocean absorbs more solar energy, thereby accelerating the warming and the melting, and exposing more open ocean, which absorbs even more solar energy.
4. Steps 1-3 continue until Arctic warms sufficiently to thaw permafrost/tundra and to destabilize underwater clathrates, thereby releasing vast amounts of methane.
5. Game over; PETM extinction looks like a picnic by comparison.