A new study has revealed that despite its apparent stability, the massive ice sheet covering most of Greenland is more sensitive to climate change than earlier estimates have suggested.
The scientists at the University of Cambridge said that this could accelerate the rising sea levels that threaten coastal communities worldwide.
In addition to assessing the impact of the increasing levels of meltwater created and spilled into the ocean each year as the climate continues to warm, the new model also takes into account the role that the soft, spongy ground beneath the ice sheet plays in its changing dynamics.
The Greenland Ice Sheet, which is the second-largest ice sheet in the world, covers 1.7 million square kilometers, is losing ice at a net annual rate of 200 gigatonnes, equating to 0.6 millimetres of sea level rise. A similarly large, but ultimately more uncertain source of sea level rise is tied to a net annual ice loss caused by increased movement of the ice sheet, which results in more ice being discharged into the ocean. Globally, sea levels are rising at three millimetres annually.
It was found that although only a small fraction of the total amount of meltwater produced on the surface is stored in supraglacial lakes, the high magnitude and frequency of lake drainage events causes the ice sheet to immediately accelerate as observed.
The study was published in the journal Nature Communications.