As global temperatures continue to rise, Antarctic marine ice sheets face an increasing risk of collapse, releasing large volumes of freshwater into the Southern Ocean. This freshwater can weaken the lower branch of the global ocean circulation that plays a vital role in distributing heat, carbon, and nutrients across the globe. Using an Earth system model, we investigate how the location, rate, and duration of freshwater input near West Antarctica affect deep ocean circulation. Our results show that freshwater reaching regions of deep water formation causes the greatest weakening. Interestingly, slower, prolonged input reduces circulation more than a rapid pulse, even when total freshwater volume is the same.
These findings highlight the critical role of freshwater extent, amount, and timing in shaping the abyssal circulation and suggest that long-term Antarctic ice melt could have far-reaching global climate impacts.
Read the full paper here: https://doi.org/10.1038/s43247-025-02589-3