Sea level rise in last 20,000 years, 2nd chart shows much larger rises than today 18,000 years ago to 8,000 years ago - particularly meltwater pulse 1A which was that 13,000 years ago approxmately...
https://www.e-education.psu.edu/earth107/node/1506
...which correlates with many of the worldwide end of the world myths
Most of that huge rise is the coming of the interglacial period, so that means many of our ancestors' settlements are about 400ft under water now. Again, so many legends of the seas swallowing the land whether that be off the Sunshine Coast or beyond Land's End or anywhere else. It is likely that the Laurentide ice sheet collapsed, for varying hypothesis why it did. My favourite is Randall Carlson's* one, imagine 100m deep of water moving at 160km/h over about 2 weeks over an enormous area - it left the scars on the NW US landscape you can still see today...
This doesn't take away from today's sea level rises, as the oceans expand (and locally, as land falls away in areas). The oceans are absorbing much of the CO2 and they are a huge system with many feedback loops.
* here are a couple of the links, blows you away to think it could all happen so suddenly if you have enough water to do it:
https://www.youtube.com/watch?v=RaHO00ISseY
https://www.youtube.com/watch?v=NqpnDMBBSGE