This study investigates the use of seawater oxygen isotopes (δ¹⁸Osw) as a tool to monitor Antarctic ice-sheet freshwater discharge (IFD) and its contribution to sea level rise. Using the isotope-enabled Community Earth System Model (iCESM) with projected IFD fluxes, the researchers found that the anthropogenic ice-sheet signal in water isotopes emerges decades earlier than salinity-based estimates. This is due to the higher signal-to-noise ratio of isotopes and the minimal impact of sea ice changes on isotopes, unlike salinity. Continuous δ¹⁸Osw measurements, particularly in the Ross Sea sector, are suggested as an early warning system for rapid Antarctic ice-sheet mass loss.

Hyuna Kim, Axel Timmermann