Deep Ocean Heat Encroaches on Antarctica, Threatening Ice Sheet Melt

Two new studies reveal that warm water trapped deep in the Southern Ocean is moving toward Antarctica, accelerating ice melt and sea-level rise. One study, published April 28 in Communications Earth and Environment, used Argo robotic floats and machine learning to show that a mass of warm water has crept closer to Antarctica over the past 20 years—the first observed shift across the Southern Ocean. Co-author Sarah Purkey of Scripps Institution of Oceanography said the ocean's circulation has changed, likening it to turning on a hot tap. Another study in Proceedings of the National Academy of Sciences found that strong winds and storms since 2016 have pushed aside cold surface water, allowing warm deep water to rise and melt sea ice. Co-author Earle Wilson of Stanford University described it as a violent release of pent-up heat. The findings underscore the need for better data networks in Antarctica, says Zachary Labe of Climate Central. The Antarctic ice sheet holds enough water to raise global sea levels by nearly 200 feet.