Scientists have made a new map of the land buried under the Greenland Ice Sheet. NASA's Earth Observatory reports that it shows hundreds of valleys as connected systems. Older maps either missed these valleys or showed them only as broken fragments.
The shape of the bedrock matters because it guides how ice moves toward the coast. Deep, continuous valleys can act as channels that carry ice from the interior out to the ocean.
A more accurate picture of the ground under the ice gives researchers better input for computer models of the ice sheet. Those models are used to estimate how Greenland's ice loss will add to global sea-level rise.
