Video: Scientists rethink impact of ice melt
Scientists discovered deep canyons beneath Greenland's ice. Credit: NASA.
"The glaciers of Greenland are likely to retreat faster and farther inland than anticipated, and for much longer, according to this very different topography we have discovered,” said Mathieu Morlighem, a UCI associate project scientist and lead author of a research paper published May 18 in the journal Nature Geoscience.
Once, scientists thought Greenland’s contribution to sea-level rise would be limited, as glaciers would melt back onto higher ground and stabilize. Morlighem's new topography shows southern Greenland's ragged, crumbling coastline is marked by more than 100 canyons beneath glaciers that empty into the ocean. Many canyons are well below sea level as far as 60 miles inland. Higher ground, where glaciers could stabilize, is much farther from the coastline than previously thought.
Buried beneath the Greenland Ice Sheet, the subcontinent's bedrock topography has been estimated using soundings from ice-penetrating radar. But the wet and fractured ice along the southern coastline cluttered the radar soundings so that large swaths of the bed remained invisible.
Morlighem and his colleagues devised an advanced technique to create a more accurate map. By combining different types of information – including radar and satellite data -- they were able to map the bed topography along Greenland's margins with unprecedented precision and detail.
Once, scientists thought Greenland’s contribution to sea-level rise would be limited, as glaciers would melt back onto higher ground and stabilize. Morlighem's new topography shows southern Greenland's ragged, crumbling coastline is marked by more than 100 canyons beneath glaciers that empty into the ocean. Many canyons are well below sea level as far as 60 miles inland. Higher ground, where glaciers could stabilize, is much farther from the coastline than previously thought.
Buried beneath the Greenland Ice Sheet, the subcontinent's bedrock topography has been estimated using soundings from ice-penetrating radar. But the wet and fractured ice along the southern coastline cluttered the radar soundings so that large swaths of the bed remained invisible.
Morlighem and his colleagues devised an advanced technique to create a more accurate map. By combining different types of information – including radar and satellite data -- they were able to map the bed topography along Greenland's margins with unprecedented precision and detail.
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