Southampton Study IDs Antarctic Sea Ice Decline Drivers

Researchers from the University of Southampton have identified a series of interconnected climate processes driving the sharp decline in Antarctic sea ice since 2015, after decades of relative stability. Satellite observations show losses equivalent to the size of Greenland, with record lows in 2022 and 2023 exceeding 2 million square kilometers below long-term averages.

The study, published in Science Advances, traces the downturn to three key events in the Southern Ocean. Around 2013, strengthened westerly winds began upwelling warm, salty Circumpolar Deep Water from ocean depths toward the surface beneath the ice. By 2015, intensified wind mixing propelled this heat into surface layers, triggering rapid melting, particularly in East Antarctica. Since 2018, a self-reinforcing feedback loop has taken hold: with less ice to melt, surface waters have grown warmer and saltier, hindering new ice formation and locking the region into low coverage.

Lead author Aditya Narayanan, a physical oceanographer at the University of Southampton, described the sequence as a buildup of deep-sea heat followed by violent mixing, ending in a cycle too warm for recovery. The analysis combined...