The pace at which Greenland is losing ice is getting faster, according to a study using a 25-year record of satellite data by the European Space Agency (ESA).
The research, published in the journal Earth and Planetary Science Letters, used radar altimetry data gathered by the European remote sensing satellite (ERS), Envisat and CryoSat missions between 1992 and 2016.
Radar altimeters record the height of the surface topography along the satellite's ground track, ESA said in statement.
They precisely measure the height of ice, water and land by timing the interval between the transmission and reception of very short radar pulses.
Over time, these measurements are used, for example, to work out how the height -- or elevation -- of huge ice sheets is changing, which, in turn, can be used to monitor ice loss.
Although the research team, working through ESA's Climate Change Initiative, found only modest elevation changes in the early 1990s, the pace of thinning is clear in the satellite observations from 2003 onwards.
"A pattern of thinning appears to dominate a large fraction of the ice sheet margins at the beginning of the millennium, with individual outlet glaciers exhibiting large thinning rates," said Louise Sandberg Sorensen, the lead author of the research paper.
"Over the full 25-year period, the general picture shows much larger volume losses are experienced in west, northwest and southeast basins of Greenland compared to the more steady-state situations in the colder far north," Sorensen said.
This highlights the strong climate sensitivity of the outlet glaciers of Greenland as well as the ongoing need for reliable, long-term monitoring of climate variables that help to improve climate models and inform policy responses, researchers said.
The Greenland ice sheet is an important cog in the global climate system with its meltwater, for example, influencing ocean circulation in the North Atlantic, they said.
Ongoing monitoring of the ice sheet is equally important in understanding its contribution to the extent and changing rate in sea-level rise.
The more recent Copernicus Sentinel-3 mission is also being used to monitor changing ice height.