September 23, 2019 3:57:42 pm
The water from melting Antarctic glaciers, flowing through the ice and beneath them, is rapidly accelerating further thawing of the continent’s ice sheets towards the sea, according to a study.
The study, published in the journal Nature Communications, is the first time researchers have found that melting on the surface impacts the flow of glaciers in Antarctica.
Researchers, including those from the University of Sheffield in the Uk, used imagery and data from satellites along with regional climate modelling and found that meltwater is causing some glaciers to move 100 per cent faster than average — by up to 400 metres per year.
According to the researchers, gravity causes glaciers to move downhill with the internal deformation of ice, and by sliding over the ground beneath them — a process lubricated by liquid water called basal sliding.
The study shows that the movement of glaciers in the Antarctic peninsula coincides with spikes in snowmelt.
The researchers add that this is due to the surface meltwater penetrating into the ice bed, and lubricating the sliding of glaciers.
As temperatures continue to rise in the Antarctic, surface melting could occur more frequently, and across a wider area, the researchers said.
According to the study, the Antarctic temperature is an important factor in determining the speed at which glaciers move towards the sea.
Ultimately, the researchers said that glaciers on the Antarctic Peninsula would behave like those in present-day Greenland and Alaska, where meltwater controls the size and timing of variations in glacier flow across seasons and years.
“Our research shows for the first time that surface meltwater is getting beneath glaciers in the Antarctic Peninsula – causing short bursts of sliding towards the sea 100 per cent faster than normal,” said co-author Jeremy Ely of the University of Sheffield.
The researchers said that they expect to see more surface meltwater than ever with increasing global average temperatures, adding that such behaviour may become more common in Antarctica.
“It’s crucial that this factor is considered in models of future sea level rise, so we can prepare for a world with fewer and smaller glaciers,” Ely added.
The discovery, according to co-author Pete Tuckett of the University of Sheffield, could have significant implications for the future rates of sea level rise.
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