Proglacial lakes are accelerating glacier ice loss
Meltwater lakes that form at glacier margins cause ice to recede much further and faster compared to glaciers that terminate on land, according to a new study. But the effects of these glacial lakes are not represented in current ice loss models, warn the study authors.
Photo courtesy of Dr Jenna Sutherland
Therefore, estimates of recession rates and ice mass loss from lake-terminating glaciers in the coming decades are likely to be under-estimated.
Many mountain glaciers now terminate in such lakes, formed as meltwater becomes trapped behind ridges of glacier debris. They are known as proglacial lakes. Climate change has increased glacier melt worldwide and this in turn has led to a dramatic increase in the size and number of proglacial lakes. But the effects of proglacial lakes on the rates of deglaciation and on glacier behaviour have previously been poorly understood.
Now, an international team of researchers, led by the University of Leeds, has quantified for the first time the influence of proglacial lakes on mountain glaciers using computer simulations. They found that the presence of a proglacial lake causes a glacier to recede more than four times further and accelerate ice flow by up to eight times when compared to the same glacier terminating on land under the same climate.
The findings, published today in the journal Geophysical Research Letters, show that a land-terminating glacier took 1000 years to succumb to the same amount of recession as a lake-terminating glacier experienced in 100 years.