Scientists' Explanation for Exploration 1C

Rate of Rise Since the Industrial Revolution

According to the Intergovernmental Panel on Climate Change (IPCC), thermal expansion and glacier melt have been the main contributors to 20th century global mean sea level rise. After 2,000 years of little change, sea level rose about 0.2 meters (8 inches) during the past century. About 75% of the observed rise (high confidence) since 1971 is from thermal expansion and glaciers in Greenland. Thermal expansion has occurred as the top 30 meters (1,000 feet) has warmed by 0.3°C (0.5°F) over the past 50 years. Since the early 1990s, the contribution of ice sheets in Greenland and Antarctica to sea level rise has increased, partly due to the warming of the adjacent ocean. The Greenland Ice Sheet is experiencing record surface melting with a record rate of loss in the past decade. If Greenland melts, there could be as much as a 7.2 meters (24 feet) rise in sea level. If the West Antarctica Ice Sheet melted, ocean levels could rise by approximately 5–6 meters (16–20 feet). If all of the ice on Antarctica melted, global sea level would rise 61 meters (200 feet).