Genomic evidence for West Antarctic Ice Sheet collapse during the Last Interglacial Period

Deep in the DNA of an Antarctic octopus, scientists may have uncovered a major clue about the future fate of the continent’s ice sheet – raising fears global heating could soon set off runaway melting.

A study pre-print published in January 2023 concludes with evidence about ice sheet collapse under a similar temperature regime as it is today.

The marine-based West Antarctic Ice Sheet (WAIS) is considered vulnerable to collapse under future climate trajectories and may even lie within the mitigated warming scenarios of 1.5–2 °C of the United Nations Paris Agreement. Knowledge of ice loss during similarly warm past climates, including the Last Interglacial period, when global sea levels were 5–10 m higher than today, and global average temperatures of 0.5–1.5 °C warmer, could resolve this uncertainty. Here we show, using a panel of genome-wide, single nucleotide polymorphisms of a circum-Antarctic octopus, persistent, historic signals of gene flow only possible with complete WAIS collapse. Our results provide the first empirical evidence that the tipping point of WAIS loss could be reached even under stringent climate mitigation scenarios.

One-Sentence Summary Historical gene flow in marine animals indicate the West Antarctic ice sheet collapsed during the Last Interglacial period.

Clue to rising sea levels lies in DNA of 4m-year-old octopus, scientists say

The Guardian: Genes of Turquet’s octopus hold memories of melting of previous Antarctic ice sheet, raising fears of what another thawing could bring.

Deep in the DNA of an Antarctic octopus, scientists may have uncovered a major clue about the future fate of the continent’s ice sheet – raising fears global heating could soon set off runaway melting.

Climate scientists have been struggling to work out if the ice sheet collapsed completely during the most recent “interglacial” period about 125,000 years ago, when global temperatures were similar to today.

The ice sheet holds enough water to raise sea levels by 3 to 4 metres with fears that global heating could soon push it towards runaway melting that would lock-in rising sea levels over centuries.