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.