evidence: Glaciers and ice sheets, large land-based formations of ice, are melting as global temperatures rise. That meltwater drains into the sea, increasing the ocean's water volume and global sea level. Melting ice has caused about two-thirds of the rise in sea level to date, one-third from land ice in Greenland and Antarctica and one third from melting ice on mountains. [...] There are other small contributions to sea level rise. Some ice sheets are so massive that they alter the Earth's gravitational pull. As ice caps melt, both the gravitation pull on Earth and the planet's rotational spin will change, affecting local sea level in complicated ways. Sea levels may rise in some places, and drop in others. Greenland's ice sheets currently pull on the surrounding ocean, creating a slight bump in the ocean in that area of the world. When the ice on Greenland melts and that pull is lost the sea level in places like Iceland and Norway will actually drop. But that water will have to go somewhere. The ocean water will redistribute so that across the globe by Japan and Hawaii sea level will rise more than the global average.