I assume you are referring to sea levels rising not Islands rising BB ? There are a number of reasons sea levels change but at the moment it is probably due mostly to a small increase in ocean temperatures causing thermal expansion. There is no nett melting of ice taking place that would cause a rise. Greenland is one of the few places losing land ice but Antarctic is gaining land ice at about the same rate. Sea ice has no effect as I am sure you know.
As to what is causing the small sea temperature rise one can only speculate on that. Some will say it is all from natural causes as in the past and others will say that man's activities are causing it. There is no proof either way.
