In a groundbreaking study published in Science, scientists have turned to the DNA of octopuses living in Antarctica’s frigid waters to uncover evidence of the West Antarctic Ice Sheet’s (WAIS) collapse during the Last Interglacial, a warm period 129,000 to 116,000 years ago. Lead author Sally Lau from James Cook University and her team analyzed the genes of geographically-isolated populations of Turquet’s octopus, discovering genetic mixing that indicated the existence of trans-West Antarctic seaways connecting the Weddell, Amundsen, and Ross seas.
The findings suggest that WAIS collapsed during the Last Interglacial when global temperatures were approximately 1.5 degrees Celsius warmer than pre-industrial levels, reflecting current conditions due to human-induced climate change. The study implies that WAIS is closer to collapse than previously estimated, posing a threat of 3.3-5 meters of long-term sea level rise if global warming surpasses the 1.5-degree target set by the Paris Agreement.
The researchers sequenced DNA across 96 octopus samples, unintentionally collected as fishing bycatch over 33 years. The study provides empirical evidence supporting the collapse of WAIS during past warm periods, emphasizing the urgent need for climate action to mitigate the potential devastating consequences of rising sea levels.
In a commentary piece accompanying the study, Andrea Dutton of the University of Wisconsin-Madison and Robert DeConto of the University of Massachusetts, Amherst praised the research as pioneering. They noted the intriguing questions raised about whether ancient history could repeat itself, emphasizing that despite uncertainties, the evidence underscores the imperative for immediate action against climate change.