Melting glaciers could trigger megatsunamis with 100m-tall waves, scientists warn

Climate scientists have raised an alarm about the rising risk of megatsunamis with waves taller than 100m as glaciers melting in Greenland trigger massive landslides .

Researchers analysed one such case of a giant tsunami that unleashed destruction in remote parts of eastern Greenland last year.

Recent tsunamis in Greenland have had devastating consequences such as the 2017 Karrat Fjord landslide that triggered a tsunami , flooding the village of Nuugaatsiaq, and killing four people.

Megatsunamis off the east coast of Greenland with waves reaching heights over 100m have also reached Europe, scientists say.

One such megatsunami in September 2023 struck Dickson Fjord in East Greenland, which seismologists noted first in social media posts and leter in report of waves hitting a military installation on Ella Island more than 50km (30miles) away.

Luckily, no people were harmed as the impacted region was a military base without personnel at the time of the tsunami.

The new study, published in the journal The Seismic Record, assessed quake signals and satellite imagery to reconstruct the series of events so that similar events could be better monitored in the future.

On 16 September 2023, a rockmass as big as a rugby stadium, and a height of about 50-100m, detached fell around 300–400m in a slope.

Scientists found that the landslide picked up glacier ice and became a mixed rock-ice avalanche before it reached the water.

They found that the resulting megatsunami has a peak height “exceeding 200m” and as tall as 60m along a 10km stretch of the fjord.

While the original cause of the landslide remains a mystery, the study unravelled the direction and magnitude of the force it exerted.

It revealed that the landslide and the resulting tsunami created a long-lasting vibration in the fjord with waves sloshing back and forth in the narrow bay of the uninhabited fjord for more than a week.

“Earthquake measuring stations up to 5,000km away registered the shaking caused by the landslide,” researchers wrote.

There was also a signal lasting a “very long period” that seismometers recorded for more than a week after the incident.

“The unusual thing about it was the long duration,” study co-author Angela Carrillo Ponce said.

Researchers believe the new findings can help better understand similar events and their possible link to climate change.

“It is obvious that the retreat of glaciers, which previously filled entire valleys, and the thawing of permafrost are leading to increased landslides,” scientists wrote.

“Climate change is accelerating the melting of glaciers and could therefore increase the risk of megatsunamis,” they added.