Swapna Kumbar , Bengaluru - Blue icebergs floating in Antarctic waters, where warming deep ocean currents now pose growing risks to continental ice stability. Deep ocean heat has been steadily advancing toward Antarctica over the past 20 years, bringing warmer waters closer to vulnerable ice shelves, according to a new long term study led by the University of Cambridge. Researchers analyzed decades of ship and Argo float data using machine learning to reveal how circumpolar deep water a warm ocean layer has expanded and shifted onto the Antarctic continental shelf, melting ice from below.

The study, published in Communications Earth & Environment, shows this hot tap effect has turned protective cold surface waters into pathways for heat that destabilizes ice shelves holding back inland glaciers. Previously shielded by cold bathymetry, Antarctica's ice now faces sustained undercutting, with potential to raise global sea levels by 58 meters if major sheets collapse. Seasonal winds, sea ice decline, and seafloor contours drive the heat incursions, particularly around West Antarctica where melting accelerates. Prof. Sarah Purkey noted the shift explains recent ice shelf losses, warning of feedback loops where melting freshwater slows ocean circulation further, trapping more heat near the continent.

Cambridge's findings confirm deep ocean warming as Antarctica's primary melt driver, urging faster emissions cuts to preserve ice shelf integrity. As heat marches poleward, the study underscores how decades of insufficient data masked this threat now clearly documented and accelerating.