NASA Missions Aim To Provide Answers on Melting Ice Sheets

摘要

Scientists trying to predict future sea-level heights need to first understand how the polar ice sheets, which hold enough water to raise global sea levels roughly 67 meters, are responding to the changing climate. Since NASA began measuring sea levels in 1992 with the radar altimeter on the U.S.-French Topex/Poseidon satellite, sea levels have risen at an average rate of approximately 3.2 millimeters per year. If that rate were to continue, sea levels would rise about 32 centimeters per century. Scientists are becoming increasingly concerned, however, that warming temperatures could accelerate melting of the Greenland ice sheet, which is three times the size of Texas, and the one in Antarctica, which is as large as the United States and Mexico combined. If that happens, sea levels could rise far more rapidly than current models predict.