Arctic tsunamis: the newest and most dangerous threat from climate change

• Boris Miranda (@ivanbor)
• BBC World News

Updated 2 hours ago

Barry Arm is a narrow sea entrance on the southern coast of Alaska. This small area, however, today poses a threat with catastrophic potential.

Geologists believe that climate change could produce a landslide of ice and rocks that could trigger a tsunami in the region.

This would be just one of the “possible devastating effects” of climate change in Alaska and other Arctic regions, according to researcher Anna Liljedahl – and they could appear in the coming years.

The geologist tells BBC News Mundo, the BBC’s Spanish-language service, that the concern about Barry Arm is very high because it could generate a much larger slide than all seen in the 20th century.

“They are different phenomena than we knew before. And the worst thing is that we believe that they will become more and more frequent,” says the geologist, from the Woods Hole Research Center, in Alaska.

She adds that the energy of a landslide like this could exceed that of a magnitude 7 earthquake.

“This is a very dangerous combination and is just one example of the dangers we have in Alaska,” he says.

In the face of these alerts, the Alaska Geological and Geophysical Studies Division expressed caution and said it permanently monitors possible land movements and landslides in the area.

The agency also says it produces models to predict how large a tsunami could be – and how it would spread.

Barry Arm Strait is located on Prince William Sound Bay, in the Gulf of Alaska.

It is an area with frequent presence of fishermen and that, before the pandemic, also received tourists on cruise ships.

A landslide of millions of tons could end these local economic activities indefinitely, in addition to putting hundreds of lives at risk.

Steve Masterman, director of Alaska’s Division of Geological and Geophysical Studies, recalls that the largest tsunami in history occurred in Alaska in 1958, producing a 520-meter wave.

He notes that the rocks released at that time were only a tenth the size of a hypothetical landslide in Barry Arm.

The gradual thawing of permafrost, a layer of frozen soil that exists in regions such as Alaska, Northeast Canada, Greenland (Denmark) or Siberia (Russia), is identified as one of the main risk factors for tsunamis.

“Permafrost holds the earth together and when the ice suddenly turns to water, conditions change and the soil can move,” explains Liljedahl.

The geologist points out that making a forecast is complex, as it is difficult to make a diagnosis of the behavior and conditions of this frozen layer, despite the numerous computer simulations already made by researchers.

“We really need to know a little more to determine how dangerous the landslide would be. That is why we believe it is necessary to produce knowledge about this threat,” he says.

Liljedahl, as well as Masterman and a group of scientists, wrote a public letter in the middle of the year warning about the risk of this landslide and a tsunami.

Alaska is not the only endangered region, explains the geologist at the Woods Hole Research Center.

British Columbia, a province in northwest Canada, and Norway also face the possibility of landslides and tsunamis due to climate change.

“As global warming continues to melt glaciers and permafrost, tsunamis produced by landslides present a major threat,” she explains.

In the past century, 10 of the 14 largest recorded tsunamis occurred in mountainous glacial areas – such as in Lituya Bay, Alaska, in the 1958 tsunami.

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