"Only a few meters beneath sea level, and what was the land now lies below the destructive surf zone. A hundred meters below sea level, and even the most violent storm waves can scarcely be felt. So, let the sea flood in, with its level jumping by meters over centuries or decades – or perhaps even years – and there simply will not be time for this wave energy to erode the landscape."
See the up side of rapid global warming and rising seas? Beautifully fossilized archeology sites for the aliens to excavate millions of years from when we've destroyed ourselves.