Ice Sheets and Sea Level Rise
The ice sheets of Greenland and Antarctica contain massive amounts of frozen water (i.e., ice) that, if broken off or melted, for instance from extended global warming or from outward ice flow, would go largely into the oceans. In view of the vast size of the oceans, covering over 70% of the Earth's surface area, many people might at first think that the addition of ice or melted ice from the ice sheets would have little impact on global sea level. The numbers prove otherwise, however, and doing the calculations helps to instill this fact as well as recognition of the vast size of the Earth's two major ice sheets. The Antarctic ice sheet, for instance, has an area far exceeding the area of the United States, and over sizable regions its ice extends to a depth of greater than 2 miles (3.2 kilometers).