Yes there is enough H2O around the planet to raise sea levels by 20m. Probably 200, even 400. coo.
In the last 15000 years sea levels have risen by 110m, as the ice caps melted. The current rate, 3m per 1000 years, would be an indiscernible blip on this graph.
Edited by Greg Locock, 04 October 2019 - 21:58.