Using the most advanced Earth-observing laser instrument NASA has ever flown in space, a team of scientists led by the University of Washington has made precise measurements of how the Greenland and Antarctic ice sheets have changed over 16 years.

In a new study published April 30 in the journal Science, researchers found the net loss of ice from Antarctica, along with Greenland’s shrinking ice sheet, has been responsible for 0.55 inches (14 millimeters) of sea level rise to the global ocean since 2003. In Antarctica, sea level rise is being driven by the loss of the floating ice shelves melting in a warming ocean. These ice shelves help hold back the flow of land-based ice.

The findings come from the Ice, Cloud and land Elevation Satellite 2 (ICESat-2), which was launched into orbit in fall 2018 and began taking detailed global elevation measurements, including over Earth’s frozen regions. By comparing the new data with measurements taken by the original ICESat from 2003 to 2009, researchers have generated a comprehensive portrait of the complexities of ice sheet change — and insights into the future of Greenland and Antarctica.

“If you watch a glacier or ice sheet for a month, or a year, you’re not going to learn much about what the climate is doing to it,” said lead author Benjamin Smith, affiliate associate professor of Earth and space sciences. “We now have a 16-year span between ICESat and ICESat-2 and can be much more confident that the changes we’re seeing in the ice have to do with the long-term changes in the climate. And ICESat-2 is a really remarkable tool for making these measurements. We’re seeing high-quality measurements that carpet both ice sheets, which let us make a detailed and precise comparison with the ICESat data.”

Previous studies of ice loss or gain often analyze data from multiple satellites and airborne missions. The new study takes a single type of measurement — height as measured by an instrument that bounces laser pulses off the ice surface — providing the most detailed and accurate picture of ice sheet change to date.

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