Greenland glacier valley map reveals potential for increased melting

Ars Technica : A new study by Mathieu Morlighem of the University of California, Irvine, and his colleagues shows that Greenland’s coastal glaciers are likely to experience more melting than expected, albeit not to the same extent as those in Antarctica . The depth of Greenland’s coastal valleys that hold glaciers has been hard to map via airborne radar, but ice-flow rates have been successfully mapped with satellites. Those maps have now been used to calculate the valley depths. Combining the flow-rate maps with known depth measurements, the researchers were able to create a much higher-resolution topographical map. Their calculations revealed that many of the valleys dip below sea level and extend much farther inland than expected. That means that as the glaciers melt and retreat, they will be exposed to the warming effect of the ocean much longer than expected. The finding could help to explain why observed melting rates have been higher than model estimates.