Huge glaciers lie under the sea on the East Antarctic Plateau. To enhance future scenarios featuring rising sea levels, it is necessary to comprehend how these glaciers will respond to increasing temperatures in the atmosphere and the ocean.
Ca’ Foscari University of Venice, in partnership with the French research center LSCE, CNRS, and Roma Tre University, carried out the research. The observations indicate that, opposed to what is claimed in the vast majority of current academic literature, coastal glaciers in East Antarctica were not stable during previous warm climatic eras when temperatures were comparable to, or warmer than, modern conditions.
The study has been published in the Nature Communications journal.
The research concentrated on coastal glaciers in the Wilkes Subglacial Basin, whose melting might cause a 3 m increase in the global sea level. The findings indicate that during past warm climatic periods, these subglacial basin ice sheets were substantially more vulnerable to rising Southern Ocean temperatures than initially assumed.
This conclusion was drawn when researchers examined the isotopic composition of water molecules in the TALDICE ice core from Talos Dome, a semi-coastal area in East Antarctica. Water isotopes enable researchers to reconstruct past temperatures.
The TALDICE ice core was compared to other Antarctic ice cores, like the one collected from the Dome C site for EPICA, and significant differences were discovered. The TALDICE ice core uncovered the consequences of events that other ice cores did not, particularly events that happened up to 340 thousand years ago during warm climatic conditions.
The comparison used a marine sediment core obtained from the continental rise next to the Wilkes Subglacial Basin to explain this phenomenon. Researchers discovered that when the climate was warmer, coastal glaciers melted, and the grounding line retreated.
The authors think that the TALDICE isotopic anomalies reflect a decrease in elevation at Talos Dome driven by ice loss and grounding line retreat in the Wilkes Subglacial Basin as a result of rising Southern Ocean temperatures. Model simulations appear to support this theory.
The coastal glaciers in the Wilkes Subglacial Basin retreated about 300 km towards inner Antarctica between 330 and 320 thousand years ago. This is the greatest retreat of the past 350 thousand years. It contributed to a 1-m global sea-level rise. We estimate that another, less significant retreat of about 100 m happened between 125 and 115 thousand years ago, and that it contributed to a 50-cm global sea-level rise.
Ilaria Crotti, Study Main Author, Ca’ Foscari University
Ilaria Crotti performed the research during her Ph.D. studies in Science and Management of Climate Change at Ca’ Foscari and Paris-Saclay University.
The research revealed vital information that will help scientists know how East Antarctica's coastal glaciers will respond to rising oceanic and atmospheric temperatures.
The research was carried out by Ilaria Crotti, along with Barbara Stenni, Professor at Ca’ Foscari University of Venice, Aurelien Quiquet and Amaelle Landais from LSCE and CNRS, and Massimo Frezzotti, Professor at Roma Tre University.
Crotti, I., et al. (2022) Wilkes subglacial basin ice sheet response to Southern Ocean warming during late Pleistocene interglacials. Nature Communications. doi.org/10.1038/s41467-022-32847-3.