Thousands of glaciers can suddenly surge, triggering avalanches and floods
The study's authors are calling for more monitoring of at-risk glaciers.
Recent research from the University of Portsmouth suggests some glaciers don’t melt. Rather, they can “explode” into motion, triggering avalanches and floods that could impact nearby communities.
Scientists identify more than 3,100 of these glaciers
Most of the world’s glaciers are shrinking, but the researchers say they’ve uncovered a “hidden threat” comprised of more than 3,100 “surging glaciers,” i.e., large ice formations that can accelerate with little warning, triggering what could be destructive associated events.
When analyzing glacier data, the team found 81 glaciers that represent the highest risk.
Most are situated in the Karakoram Mountains in High Mountain Asia, which sit atop populated areas.
"These glaciers tend to be large, close to people, and prone to repeated surging," the authors say.
The Canadian connection
While the glaciers identified in the study are concentrated in the Arctic, High Mountain Asia, and the Andes, there are parts of Canada’s Arctic are where surging glaciers could become more common in the years ahead.
Rising temperatures and more extreme weather events could make sudden glacier movements even harder to predict, the researchers say.
"The challenge we face is that just as we're starting to develop a more comprehensive understanding of the mechanisms behind glacier surges, climate change is rewriting the rules. Extreme weather events that might have been rare even 50 years ago could become triggers for unexpected surges," study co-author Professor Gwenn Flowers, from Simon Fraser University, said.
"Given that surges cause hazards in some settings, this makes protecting vulnerable communities much more difficult."
Why do some glaciers surge?
Glacier surges occur when normally slow-moving ice suddenly speeds up, pushing ice to the front of the glacier and causing it to advance. Surges can last for several years, with some glaciers repeating the cycle often, with prolonged quiet periods in between.
"Surge-type glaciers are very unusual and can be troublesome," lead author Dr. Harold Lovell, Senior Lecturer and glaciologist from the University of Portsmouth's School of the Environment and Life Sciences, said in a statement.
"As a friend and fellow glaciologist once put it, they save up ice like a savings account and then spend it all very quickly like a Black Friday event. But while they only represent 1 per cent of all glaciers worldwide, they affect just under one-fifth of global glacier area, and their behaviour can result in serious and sometimes catastrophic natural disasters that affect thousands of people."
The climate change factor
The researchers say surging activity can cause a glacier to lose a large amount of ice, making it more sensitive to further ice loss due to warming temperatures brought about by climate change.
"By drawing on previous studies, we have been able to piece together the growing body of evidence that shows how climate change is affecting glacier surges, including where and how often they happen," Dr. Lovell said.
"This includes instances of extreme weather such as heavy rainfall events or very warm summers triggering earlier than expected surges, suggesting an increasing unpredictability in their behaviour."
Major hazards
The study identifies the main hazards surging glaciers can pose to nearby communities.
They include:
Glacier advance, where a glacier moves inland and onto roads or buildings.
River blockages and meltwater bursts that can cause flooding.
Sudden glacier detachments, which can produce ice and rock avalanches.
Crevassing that could make areas where glaciers are used as routes unstable.
Risks to ships and marine tourism, due to the unpredictability of the surges.
The study's authors are calling for increased glacier monitoring via satellites, alongside improved modelling and projections, and more field observations.
"This research is extremely important because understanding which regions have concentrations of surging glaciers helps us plan monitoring efforts and understand future behavior. Knowing which specific glaciers pose the greatest risks can help protect communities, especially those most at risk. But the increasing unpredictability means we need much better surveillance and forecasting capabilities,” Dr. Lovell said.
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