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3. Greenland Ice Sheet: Disappearing Lakes on a Massive Scale
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Covering around 660,000 square miles of Greenland's surface and averaging thickness of one mile, the Greenland Ice Sheet is a magnificent natural phenomenon. Rather than a homogeneous, featureless plain, this large swath of ice is a dynamic scene dotted with many brilliant, turquoise blue lakes known as supraglacial lakes. Formed from melting surface ice, these lakes have attracted close scientific attention because their tendency to vanish quickly—sometimes within a few hours or days.
2015 saw a particularly spectacular event that drew glaciologists all over. Two supraglacial lakes on the ice sheet, which had been steady for years, vanished out of sight. The loss was not a small-scale event; billions of gallons of water vanished in a few weeks, leaving empty basins where once vivid blue lakes existed. This occurrence spurred a frenzy of investigation as experts tried to explain the processes underlying such fast drainage.
Later studies found that these lakes had leaked through moulins—vertical fissures in the ice. From the surface all the way to the bottom of the ice sheet, these cracks provide a direct passage for surface water to reach the bedrock underneath. The process is sometimes self-reinforcing; as water runs across these fissures, it can deepen them by hydraulic fracturing and melting, maybe resulting in even rapid drainage going forward.
Supraglacial lake emergence and disappearance on the Greenland Ice Sheet is closely related to climate change. More often and bigger supraglacial lakes arise as global temperatures rise since the rate of surface melting on the ice sheet rises. Not only is the fast drainage of these lakes a curiosity; it also has important consequences for the general dynamics and stability of the ice sheet.
Large amounts of water draining to the base of the ice sheet can function as a lubricant, therefore perhaps speeding the ice towards the ocean. Basal sliding is this mechanism that might help to explain quicker sea-level rise and glacier loss. Further influencing ice sheet behavior could be the complicated series of hydrological and thermal changes caused by the flood of surface meltwater to the base of the ice sheet.
In glaciology and climate science, the study of supraglacial lakes on the Greenland Ice Sheet has grown to be a vital focus. To better grasp the creation, growth, and drainage of these lakes, scientists are using a variety of approaches including computer modeling, ground-based observations, and satellite photography as well as Predicting the future behavior of the Greenland Ice Sheet and evaluating its possible contributions to world sea-level rise depend on this research as well.
One striking example of the complicated and often unexpected manner in which climate change is altering Earth's cryosphere is the phenomena of disappearing supraglacial lakes. The dynamics of ice sheets and glaciers are probably going to grow more erratic as the world warms, which emphasizes the urgent need of ongoing research and monitoring in these vital regions.
