Abstract
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.
Competing Interest Statement
The authors have declared no competing interest.
