Ocean bays that squeeze West Antarctica are home to two distinct populations of Turquet’s octopus (Pareledon turqueti). Their ancestors’ shared secrets do not bode well for the future health of our planet.
A recent DNA analysis of the two geographically separate octopus populations, published earlier this year ahead of peer review, indicates they were once part of one large family.
This “direct historical connection” suggests that about 125,000 years ago, the massive 2.2 million cubic kilometers (530,000 cu mi) West Antarctic Ice Sheet separating the two bays had completely collapsed into the sea.
Scientists who sequenced the genomes of octopus populations in both the Weddell and Ross Seas found evidence of ancestral gene flow between the two populations about 70,000 years ago, imagine that “An ancient seaway probably once opened across the West Antarctic ice sheet, directly connecting the present-day Weddell Sea and the Ross Sea”.
“This can only be facilitated by a complete collapse of the West Antarctic ice sheet during an interglacial period, which we conclude occurred approximately between 68 and 265. [thousand years go],” she to write.
If it happened then, it could very well happen again, especially as global temperatures reach a similar threshold today.
At the moment, scientists don’t really know if West Antarctica is at risk of complete collapse due to the climate crisis. It’s one of those great uncertainties left to solve in climate models.
While some experts warned of the disaster in the region already 50 years ago, other climate models made only 10 years ago predicted no significant ice loss in Antarctica within the century.
How wrong that turned out to be.
Today, West Antarctica is draining melting icebergs the size of major metropolises much faster than the rest of the continent.
One of its glaciers is known as the “Doomsday Glacier,” because if it collapses it could single-handedly cause 65 centimeters of sea level rise. Climate scientists recently warned that the glacier was holding on “by its fingernails”.
So how long will the region remain dangling from the edge of a cliff?
Of course, the collapse in the past was due to a natural cycle in the Earth’s climate. It was not caused by rapid global warming, caused by human emissions of fossil fuels during what should be a planetary cold snap, as it is today.
If the entire West Antarctic Ice Sheet collapses from man-made global warming and forms an archipelago in the southern ocean, the resulting environmental catastrophe will be difficult to fathom.
Scientists predict that global sea levels could rise by 3.3 to 5 meters (11 to 17 feet), disrupting water circulation in the world’s oceans. drastically reform the coastlines of continents.
“Currently, the future collapse of the West Antarctic ice sheet on centennial timescales is considered a low-probability process,” researchers of the octopus paper to write.
But even the most optimistic future models predict that air temperatures will reach 1.2 to 1.7 °C by 2100, and as the authors assignthat is “potentially within the tipping point of future West Antarctic ice sheet collapse”.
Currently, more than half of the ice shelves that support the Antarctic ice sheet are on the verge of collapse, and if they crumble, it could potentially lead to irreversible losses.
If Turquet’s octopuses in the southern ocean are ever reunited with their long-lost relatives, it means our planet is in real trouble.
The study is published in bioRxiv.