climate change can cause gigantic tsunamis in the Southern Ocean by possible underwater landslides, a new study warns.

By drilling into sediment cores hundreds of meters below Antarctica, scientists found that layers of loose sediment formed during earlier periods of global warming (3 million and 15 million years ago), causing massive tsunamis off the coast of North America. South, New Zealand and Southeast Asia.

Because climate change is warming the oceans, researchers believe soThere is a chance that these tsunamis will erupt again. Their findings were published May 18 in the journal Nature Communications.

“Undersea Landslides pose a major geological hazard with the potential to generate tsunamis that can cause major loss of lifeJenny Gales, professor of hydrography and ocean research at the University of Plymouth in the United Kingdom, said in a statement. “Emphasize our findings how we urgently need to improve our understanding of how global climate change may affect the stability of these regions and the potential for future tsunamis”.

The researchers first found evidence of ancient landslides off the coast of Antarctica in 2017 in the eastern Ross Sea. Trapped beneath these landslides are layers of weak sediment teeming with fossilized marine life known as phytoplankton.

The scientists returned to the area in 2018 and drilled deep into the seabed to extract sediment coreslong, thin cylinders of the earth’s crust that show, layer by layer, the geological history of the region.

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By analyzing sediment cores, scientists found that the weak sediment layers formed over two periods, one about 3 million years ago in the warm period of the mid-Pliocene and the other about 15 million years ago during the optimal Miocene climate. During these times, the waters around Antarctica were 5.4 degrees Fahrenheit (3 degrees Celsius) warmer than today, causing algal outbursts that, after they died, littered the seafloor with rich, slippery sediment. , making the region prone to landslides.

“During later cold climates, these slippery layers became covered with thick layers of gravel spewed out by glaciers and icebergs,” said Robert McKay, director of the Antarctic Research Center at Victoria University of Wellington and co-science director of the International Discovery Program. the oceans.

The exact cause of the past submarine landslides in the region is not certain, but researchers have found a possible culprit: the melting of ice from glaciers as a result of a warmer climate. The end of Earth’s periodic ice ages caused ice sheets to contract and retreat, relieving the load on Earth’s tectonic plates and causing them to rebound in a process known as isostatic rebound.

After the weak layers of sediment accumulated in sufficient quantities, the continental rise of Antarctica produced earthquakes that caused the coarse gravel on top of the smooth layers of the continental shelf edge to slide, triggering landslides that produced tsunamis.

The scale and magnitude of ancient ocean waves is unknown, but scientists noted two relatively recent underwater landslides that produced massive tsunamis and caused significant loss of life: the 1929 Grand Banks tsunami that sent waves 40 feet high and killed about 28 people the Canadian coast of Newfoundland; and the 1998 tsunami in Papua New Guinea that sent waves 15 meters high that claimed 2,200 lives.

With many layers of sediment buried beneath the Antarctic seafloor and glaciers atop the landmass slowly melting, the researchers warn that if they’re right that melting glaciers caused them in the past, future landslides and tsunamis could happen again.