Giant underwater landslides induced in Antarctica by the climate crisis might lead to tsunami waves with the potential to cause a “substantial loss of life far from their origin”, according to a new study.
Underwater landslides are global hazards that can displace large volumes of sediment and generate killer tsunamis.
For instance, a submarine landslide near Papua New Guinea in 1998 generated tsunami waves that killed 2,200 people.
Researchers, including those from the University of Plymouth in the US, discovered that between 3 and 15 million years ago, during a past period of global heating, loose sediment layers slipped in Antarctica, triggering giant tsunamis that ravaged the shores of New Zealand, southeast Asia and South America.
In the new study, published recently in the journal Nature Communications, scientists found extensive layers of weak, fossilised and biologically rich sediment hundreds of metres beneath the seafloor.
The research highlights that these layers formed at a time when temperatures in Antarctica were up to 3C warmer than they are today.
Amid current human-driven rapid climate change, leading to rising sea levels and shrinking ice sheets, scientists warned that underwater landslides in Antarctica may once again generate tsunami waves that stretch across the Southern Ocean.
“Large landslides along the Antarctic margin have the potential to trigger tsunamis, which may result in substantial loss of life far from their origin,” study co-author Amelia Shevenell said in a statement.
The landslides were first discovered in the eastern Ross Sea in 2017 by an international team of scientists during the Italian ODYSSEA expedition.
When researchers revisited the area in 2018, they collected sediment cores extending hundreds of metres beneath the seafloor.
Scientists found that the sediments uncovered formed under areas of underwater landslides.
Analysis of these layers revealed microscopic fossils that painted a picture of what the climate would have been like in the region millions of years ago and how they created weak layers deep under the Ross Sea – a bay in Antarctica that is said to be the world’s largest marine protected area.
The weak sediment layers, according to scientists, make the area susceptible to failure in the face of earthquakes, leading to giant tsunamis emerging from the region.
“Submarine landslides are a major geohazard with the potential to trigger tsunamis that can lead to huge loss of life. The landslides can also destroy infrastructure including subsea cables, meaning future such events would create a wide range of economic and social impacts,” study co-author Jenny Gales said.
“Our findings highlight how we urgently need to enhance our understanding of how global climate change might influence the stability of these regions and potential for future tsunamis,” Dr Gales said.