Page 17: of Marine Technology Magazine (January 2025)

the atmosphere and surface waters become cooler and denser. the densest and deepest waters of the global ocean are formed.

Sea ice cover around Antarctica hit a record low in 2023, “However, this cooling and subsequent sinking of waters with ice reductions in strong loss regions 50 to 80 % below previously covered by sea ice has the potential to release the 1991 to 2020 winter average. Ocean heat loss to the at- deeper warm waters that would normally be kept away from mosphere at some locations has more than doubled and an ice by an insulating surface layer. In turn this has the potential increase in storms has been observed around much of the high for increasing sea ice melt in future years”. latitude Southern Ocean by up to seven days a month. “Further analysis is urgently needed to understand these pro-

Previous analysis of the long-term impacts of declining Ant- cesses and their complex feedbacks, and determine how the arctic sea ice by co-author Dr Holly Ayres, formerly at the massive decline of winter sea ice in 2023, and again this year,

University of Reading and now at NOC, shows that enhanced will impact the Southern Ocean circulation. This is key to under- ocean heat loss can also affect the climate as far away as the standing the climatically critical ocean uptake of atmospheric

Tropics and the Northern Hemisphere. heat and carbon, and the rate of melt of the Antarctic continent.”

She says, “My work analyzed a climate model experiment where “We now need a more detailed understanding of the strength- the amount of ice was arti? cially reduced. However, I didn’t ex- ening ocean heat loss in the regions of declining Antarctic sea pect to see a real-world ice decline as large as that observed in ice and its wider impacts,” adds Professor Josey. 2023 with such strong consequences for the ocean heat loss.” “This is vital to understand how the increased number of

The study also found that the disappearing sea ice is allowing storms are linked to the extra heat supply into the atmosphere the ocean surface waters to change their properties particu- and for determining long term societal risks, including poten- larly density. Professor Josey notes, “The massive increase in tial changes to weather conditions in the decades ahead in lo- ocean heat loss to the atmosphere is increasing the density of cations far removed from Antarctica.” water at the sea surface to values not previously seen in the “Critically, we need to use our ocean and climate simulations newly ice-free regions.” to understand how the major increase in heat loss and increased

Co-author Dr. Andrew Meijers, from the British Antarctic Sur- surface water density impacts the wider ocean circulation.” vey, explains further, “The location of this new denser surface Read the full article in Nature: water is relatively far from the sites at the Antarctic shelf where https://www.nature.com/articles/s41586-024-08368-y www.marinetechnologynews.com 17

MTR #1 (1-17).indd 17 2/3/2025 11:27:23 AM