Overview
- The peer-reviewed study, published Tuesday in Communications Earth & Environment, finds that a relatively warm mass called circumpolar deep water has expanded and moved toward Antarctica across most longitudes.
- Scientists combined decades of detailed ship transects with continuous Argo float data and used machine learning to build monthly ocean records spanning the past 40 years.
- The encroaching deep water can flow under ice shelves, thin the floating buttresses that hold back inland ice, and raise the risk of faster sea-level rise for coastal communities.
- The authors say the causes of the shift are not yet settled, pointing to natural variability and wind changes tied to human-driven warming as possibilities that need further study.
- Redistribution of heat in the Southern Ocean could change how the ocean stores heat, carbon and nutrients and may affect large-scale circulation, including the Atlantic Meridional Overturning Circulation.