Discoveries

January 01, 2024

The Melting Point

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Scientists have long wondered about the West Antarctic Ice Sheet (WAIS) – specifically, the last time it collapsed.

If it melts completely, this ice sheet packs enough water to raise global sea levels by more than 16 feet.

Now, a new genetic study of Antarctica’s octopuses unveiled some new clues to the frozen continent’s history and possibly its future, Smithsonian Magazine reported.

Recently, a research team looked into the genetic history of Turquet’s octopuses, a small cephalopod species that has been living around the icy landmass for four million years.

The populations of Turquet’s octopuses in Antarctica’s Ross Sea and Weddell Sea are separated by the impassable WAIS. As a result, they rarely move far from where they live. But genetic testing shows that at one point, the two populations interbred, which means they were able to mix due to the collapse of the WAIS.

After sequencing the DNA of 96 octopuses, researchers found that the populations in the Weddell Sea and Ross Sea interbred between about 139,000 and 54,000 years ago, during a period known as the Last Interglacial, according to a new study.

Their findings fit with scientists’ suspicions that the collapse of the WAIS had occurred during that time when the was about 0.9 to 2.7 degrees Fahrenheit warmer than pre-industrial averages.

Other researchers praised the study as the “first biologic evidence that’s being used for past collapse,” noting that further investigation can reveal more about ice sheet’s melting in modern times.

Current global average temperatures linger around 2.2 degrees Fahrenheit higher than the pre-industrial average and the warming oceans have left WAIS in a precarious situation.

This story originally appeared in the January 01, 2024 newsletter, A Decisive New Year.