Having accurately reproduced the hydrological response of ice flow along the western margin of the ice sheet, the authors were able to subsequently evaluate the sensitivity of flow to warmer climatic conditions, resulting in more meltwater on the surface. This showed stable annual flow under present-day conditions, but a more vulnerable ice sheet in warmer years when more meltwater reaches the bed via frequent high-discharge drainage events, not only because of the emptying of supraglacial lakes such as the ones currently observed, but also because daily variations in melt volume will become equally large.
The study concludes that there is a limit on how much water can be stored in the soft ground beneath the Greenland Ice Sheet. This makes it sensitive to climate change as well as to increased frequency of short-lived, but extreme, meteorological events including rainfall and heatwaves.
The work was funded by the Natural Environment Research Council (NERC).
The paper, titled “Sensitive Response of the Greenland Ice Sheet to Surface Melt Drainage over a Soft Bed” was published on September 29 in the journal Nature Communications: doi:10.1038/ncomms6052
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Source: University of Cambridge.