Massive underwater landslides in Antarctica triggered by past climate change: Study

Scientists have found what they think to be the origin of massive underwater landslides in Antarctica, which might have resulted in tsunami waves that swept throughout the southern hemisphere hundreds of thousands of years ago. The explanation is well-known: climate change.

But not today's climate change, but climatic change in the distant past. A team of researchers led by Jenny Gales, a lecturer at the University of Plymouth, identified layers of fragile, fossilised, environmentally rich sediments hundreds of metres beneath the seafloor.

According to a study published earlier this month in Nature Communications by the researchers, these weak layers left the area susceptible to collapse when earthquakes or other seismic activity occurred.

Based on research, those thin layers originated when temperatures in Antarctica were up to 3 degrees Celsius hotter than they are now, and when sea levels were higher and ice sheets were considerably less than they are now.

If all of that sounds familiar, it's because our planet is already undergoing many similar changes, including rising sea levels, warmer oceans, and disappearing ice sheets. This suggests that such massive underwater landslides are likely to occur again if climate change continues unchecked.

“We need to better understand the extent of the weak layers that sit beneath the submarine landslides in Antarctica that make this area unstable. We also need to better understand exactly how climate is influencing the triggering of these submarine landslides. This will give us a better understanding of the future risks posed by these hazardous events,” Jenny Gales told the Indian Express.

Risks of underwater landslides

Underwater landslides, according to Gales, are a massive danger with the potential to create tsunamis that can result in large casualties. These landslides have the potential to harm infrastructure, including subsea cables. "The submarine landslides are dated to around 400,000 years ago, 1.72 million years ago, and 12.14 million years ago, and any tsunami associated with these submarine landslides would have happened directly after the submarine landslide events," Gales explained, referring to landslide evidence discovered in 2017 by an international team of scientists during the Italian Odyssea expedition.

The scientists revisited to the location in 2018 as part of an expedition that gathered sediment cores from hundreds of metres below the seafloor. They studied the materials to determine what the climate would have been like in the region millions of years ago and how it generated the weak layers beneath the ocean floor.