When researching glacial melting, scientists must consider not only how much ice is being lost, but also how quickly. Recent studies show that the movement of ice towards the ocean from both of the major ice sheets has increased …show more content…
Since the mid-19th century, sea level has been rising, likely primarily as a result of human-induced climate change. During the 20th century, sea level rose about 15-20 centimeters (roughly 1.5 to 2.0 mm/year), with the rate at the end of the century greater than over the early part of the century (8, 9). Satellite measurements taken over the past decade, however, indicate that the rate of increase has jumped to about 3.1 mm/year, which is significantly higher than the average rate for the 20th century (10). Projections suggest that the rate of sea level rise is likely to increase during the 21st century, although there is considerable controversy about the likely size of the increase. As explained in the next section, this controversy arises mainly due to uncertainties about the contributions to expect from the three main processes responsible for sea level rise: thermal expansion, the melting of glaciers and ice caps, and the loss of ice from the Greenland and West Antarctic ice sheets. Before describing the major factors contributing to climate change, it should be understood that the melting back of sea ice (e.g., in the Arctic and the floating ice shelves) will not directly contribute to sea level rise because this ice is already floating