Antarctic sea ice loss triggers historic ocean shift in two decades
Antarctic Intermediate Water has become saltier and denser since 2016. Scientists say they have never seen this kind of change.
A University of Melbourne study found a major shift in Antarctic Intermediate Water. Antarctic Intermediate Water sits 500 to 1500 metres below the surface.
The layer acts as a climate buffer, absorbing excess heat and carbon dioxide. From 1995 to 2015, the layer stayed stable thanks to Antarctic summer ice melts.
From 2016 to 2024, Antarctic Intermediate Water abruptly became saltier, denser, and deeper as sea ice hit record lows. "Since we have records in oceanography, we have never seen this water change," lead researcher Bishakhdatta Gayen said.
The last comparable shift took around 130,000 years. It happened at the end of the previous ice age.
This one happened in just eight years. Scientists warn the weakened layer could push excess heat deeper into the ocean.
This could affect weather patterns and sea levels across the southern hemisphere.
- 500 to 1500 metres
- Depth range
- 2016 to 2024
- Change period
- 130,000 years ago
- Last comparable shift
- 4000 robotic floats
- Observational data sources
Why it mattersThis ocean change is unlike anything we have seen before. It suggests the southern hemisphere's climate is shifting faster than climate models predicted.
AustraliaAustralia sits in the southern hemisphere and depends on ocean stability for weather patterns and fisheries; faster warming and shifting sea levels could affect both agriculture and coastal communities.
✓ Claims checked against the source and corrected before publish. checked 2 h ago
Open this story in InSnip →
