I don't understand this statement. To me the statement means that some places in the ocean will warm faster than others and those local places will have local sea level rises bigger than elsewhere due to the local warming causing water expansion. Sea level is determined by many things, mostly gravity, but I don't see how a local volume increase will last very long at all (ie it will dissipate at the speed of sound in water. Like a tsunami but really small and continuous). Misquoted perhaps?
Truly, only Gell-Mann amnesia allows me to keep reading the news. Probably worth stopping.