Scientists look back in time to before the last ice age

              Scientists have revealed a groundbreaking 3D map of Greenland ice sheet allowing them to look back in time.
               Using ice-penetrating radar data collected by NASA's Operation ice bridge, the project allows scientists to determine the age of large swaths of the second largest mass of ice on Earth.
                They say it could also help predict the future for the sheet, an area containing enough water to raise ocean levels by about 20 feet.
                 Scientists can now determine the age of large swaths of the ice sheet and see how the sheet evolved.
                  Greenland's ice sheet has been losing mass over the past 20 years due to warming temperatures.
                   Scientists are studying the ice during different climate periods so they can better predict how the ice sheet will respond in the future.
                    'This new, huge data volume records how the ice sheet evolved and how it's flowing today,' said Joe MacGregor, the study's lead author, a glaciologist at The University of Texas.
                       The ice-penetrating radar, called crisis radar, has the ability to detect the visible layers in ice that one would read in ice cores.