evidence: Perhaps the biggest, most obvious effect is that glaciers and ice caps melt faster than usual. The meltwater drains into the oceans, causing sea levels to rise. Glaciers and ice caps cover about 10 percent of the world’s landmasses. They hold between 70 and 75 percent of the world’s freshwater. If all of this ice melted, sea levels would rise by about 70 meters (230 feet). The Intergovernmental Panel on Climate Change states that the global sea level rose about 1.8 millimeters (0.07 inches) per year from 1961 to 1993, and about 3.1 millimeters (0.12 inches) per year since 1993.