beretta, I use the word 'stable' to mean not changing. If sea levels were stable it would mean they are steady, not rising or falling. Interestingly my use of the word is the same as Oxford, and the same as Merriam Webster.
What do you mean by 'stable'? If you think a 'stable' sea level means the sea level is rising, what do you call an unchanging steady sea level - unstable?
PS you forgot to post the link to the climate change denier/delayer website you copied and pasted.