2 days ago
New sea ice research results ‘shocking'
Braving the midwinter conditions at noon near Scott Base, are (from left) science technician Hue Tran, with members of the Scott Base search and rescue team Daniel Beveridge, William Stewart and Alex Sewell, who helped to install the University of Otago's sea ice monitoring station (Sims) in McMurdo Sound. PHOTO: STEPHEN TRIMBLE
Is it midnight or midday — at this time of year, it is almost impossible to tell at Scott Base.
Staff from the Antarctic base recently spent their lunch break on the sea ice in McMurdo Sound, where they installed the University of Otago's sea ice monitoring station (Sims), for the 2025 winter season.
University of Otago sea ice physicist Associate Prof Inga Smith and surveyor Dr Greg Leonard have been collecting measurements from the monitoring station for more than 20 years.
The measurements help scientists understanding the seasonal dynamics of sea ice changes, which have important implications for the global climate.
Recently, researchers found evidence of a major shift of the Southern Ocean which could accelerate climate change for the whole planet.
Typically, as global heating melts the ice around Antarctica, climate scientists would expect saltier water at the surface of the ocean to be replaced by fresh water, because melting ice typically makes the ocean fresher.
But new satellite data shows the opposite is happening, which has caught scientists off-guard.
It is happening because the salt water is drawing up heat and carbon dioxide from the deep ocean, making it harder for sea ice to regrow.
It had the potential to accelerate ice loss and global heating.
Assoc Prof Smith said the new results were "shocking" for those researching Antarctic sea ice.
The Southern Ocean plays an essential role in regulating the Earth's heat and carbon, and its disruption could trigger cascading effects on other ocean circulation systems, with potential consequences as far away as Europe.
She said in a warming world, fresher water from melting of land-based ice sheets and floating ice shelves would be expected to dominate at the ocean surface.
Instead, the ocean surface was getting warmer and more salty, right at the time the extent of the sea ice shrank.
Researchers would explore this further in the near future, she said.
