Scientists have used computer models to create a series of maps that show how susceptible coastal cities and island countries are to the sea rising at different levels. the maps show that a 1-meter rise would swamp cities all along the u. s. eastern seaboard. a 6-meter sea level rise would submerge a large part of florida. thermal expansion has already raised the oceans 10 to 20 centimeters. the most likely cause, directly and indirectly, for such a rise in sea level is a) global warming. b) increased sedimentation. c) change in ocean salinity. d) decrease in ocean density.