"A huge ice sheet appears to have melted about 120,000 years ago, when temperatures were similar to those on Earth today, according to a DNA study that mapped octopus movements."
"Scientists have long wondered whether the West Antarctic Ice Sheet is a ticking time bomb in terms of sea level rise. New evidence from the DNA of a small octopus that lives in the Southern Ocean suggests that the ice sheet is indeed at risk of collapsing, according to a study published on Thursday in the journal Science.
The research doesn’t predict when this might happen, but it indicates that 1.5 degrees Celsius of global warming over the preindustrial global average, or perhaps even less than that, might be a tipping point for the ice sheet. The Earth is close to that temperature level now.
Several distinct populations of Pareledone turqueti, commonly known as Turquet’s octopus, live in the waters around Antarctica today. These octopuses crawl along the sea floor and generally don’t stray far from home. A few individuals or their eggs might occasionally drift on currents to neighboring groups, but populations in the Ross Sea and Weddell Sea are separated by the impassable West Antarctic Ice Sheet.
And yet, genetic analysis of octopuses from different locations around Antarctica show that these two populations were mingling and swapping DNA about 120,000 years ago. This was a time in Earth’s history called the Last Interglacial period, before the most recent ice age, when temperatures were similar to today."
Delger Erdenesanaa reports for the New York Times December 21, 2023.
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