In the cold reaches of the Southern Ocean, a record failure of sea ice to re-form in 2023 left wide stretches of water open to the sky for the first time in memory, and a study now published in Nature suggests the sea is paying for it in a familiar human currency: more heat released to the air and more storms gathering above it. Such changes are part of a longer story in which the polar world has been losing its white cover for years, and the ocean, which absorbs most of the warmth our emissions trap, is quietly rearranging how it holds that heat. Whether this single unusual winter becomes a l
Record Antarctic Sea Ice Loss Is Fueling More Storms Over the Southern Ocean, Study Finds
A record amount of ice failed to re-form over the winter.
Mark
So what's new here? We already knew Antarctic sea ice was shrinking.
Mimi
The new part is the atmosphere. Earlier work focused on penguins, ice shelves and carbon uptake. This study looks at open water losing heat to the air, and storms becoming more frequent over those areas.
Luke
How firm is the storm finding? What did they actually measure?
Mimi
They used satellite imagery, ocean and atmospheric data, and wind and temperature measurements across three regions with unusually high ice loss. In those regions, June and July storm frequency rose by up to 7 days per month in 2023 versus 1990 to 2015.
Luke
Note the words "up to." That's the maximum, not an average across all the regions. The report doesn't say how the figure varies between them.
Mark
And the heat loss figure?
Mimi
Some newly ice-free areas lost double the heat compared with a steadier period before 2015.
Luke
Again, "some" areas. The coverage doesn't say how many, or whether all three regions did.
Mark
Why does heat loss matter beyond the storms?
Mimi
The ocean stores over 90 percent of the excess heat from greenhouse gases. If the way Antarctic bottom water absorbs and stores heat changes, circulation and climate could shift.
Luke
That's a possibility the authors raise, not a result. They say further analysis is needed.
Mark
And the warning about the tropics and Northern Hemisphere?
Mimi
It's conditional: repeated low-ice winters would strengthen these impacts and are likely to cause changes further afield.
Luke
Likely, not demonstrated. It's a projection from one year of record loss, and whether low ice recurs is still unknown.
Il Polso
- A record loss of Antarctic sea ice in 2023 left large Southern Ocean areas suddenly exposed to the atmosphere.
- Some newly open waters released roughly double the heat they did before 2015, feeding a visible rise in storms.
- Storm frequency over former ice zones climbed by as much as seven days a month in June and July compared with 1990 to 2015.
- Scientists are racing to determine whether repeated low-ice winters will deepen these shifts and reach Antarctic bottom water circulation.
- The warning is that a run of ice-poor winters could reshape climate far beyond the poles, in the tropics and the Northern Hemisphere.
In the cold reaches of the Southern Ocean, a record failure of sea ice to re-form in 2023 left wide stretches of water open to the sky for the first time in memory, and a study now published in Nature suggests the sea is paying for it in a familiar human currency: more heat released to the air and more storms gathering above it. Such changes are part of a longer story in which the polar world has been losing its white cover for years, and the ocean, which absorbs most of the warmth our emissions trap, is quietly rearranging how it holds that heat. Whether this single unusual winter becomes a lasting pattern remains an open question, and the answer may decide how far its effects travel from the ice toward distant tropics and the north.
A study published Wednesday in the journal Nature reports that the record loss of Antarctic sea ice in 2023 has been followed by more frequent storms over parts of the Southern Ocean that were newly left open to the sky.
The damage from vanishing Antarctic ice is already known: fewer penguins, melting ice shelves, and a weakened ocean ability to absorb carbon dioxide. This research turns to something less visible, the ocean releasing more heat into the atmosphere and the storms that come with it. Sea ice has been shrinking across Antarctica since 2016, but 2023 stood apart, as a record amount failed to re-form over winter.
Simon Josey of the UK's National Oceanography Centre and his colleagues examined three regions with unusually heavy ice retreat that year, using satellite images, ocean and atmospheric data, and wind and temperature measurements. In some newly ice-free zones, heat loss from the ocean was double its pre-2015 level. Storm frequency in June and July 2023 rose by as much as seven days a month over former ice areas.
The researchers suggest the effects may reach far beyond polar waters, since oceans store most of the excess heat from greenhouse gases and may alter how cold, dense Antarctic bottom water stores that heat. They caution that more analysis is needed. Their clearest warning is that repeated low-ice winters would strengthen these impacts and could bring profound change to the tropics and the Northern Hemisphere. What to watch now is whether such winters return.
A study published Wednesday in the journal Nature reports that the record loss of Antarctic sea ice in 2023 has been followed by more frequent storms over parts of the Southern Ocean that were newly left open to the sky.
The consequences of vanishing Antarctic sea ice are already well documented. Scientists know it can reduce penguin numbers, allow ice shelves to melt in warmer water, and hamper the Southern Ocean's ability to absorb carbon dioxide. This peer-reviewed study looks at a different effect: the ocean giving up more heat to the atmosphere, and a rise in storms that goes along with it.
Sea ice across Antarctica has been shrinking on a large scale since 2016. But 2023 stood apart from the years before it. A record amount of ice failed to re-form over the winter, leaving open water where ice would normally sit.
Simon Josey of the UK's National Oceanography Centre and his colleagues concentrated on three regions that saw unusually heavy ice retreat that year. They drew on satellite imagery, ocean and atmospheric data, and measurements of wind and temperature. In some of the newly ice-free areas, they found heat loss from the ocean was double what it had been during a steadier period before 2015.
The authors also found "increases in atmospheric-storm frequency" over the regions that used to be covered by ice. In the areas where sea ice declined, they wrote, June and July storm frequency in 2023 rose by as much as 7 days per month compared with the 1990 to 2015 period.
The researchers say the heat loss could matter well beyond the polar waters. Oceans regulate the climate and act as a carbon sink, storing more than 90 percent of the excess heat trapped near Earth's surface by greenhouse gas emissions. The study points in particular to the possibility that sea-ice retreat could change how a deeper layer of cold, dense Antarctic bottom water absorbs and stores heat, with implications for ocean circulation and the wider climate system.
The authors stress that more detailed analysis is needed on the possible climate impacts, including whether the retreat could reach even further. They did, however, spell out a warning about repetition. "Repeated low ice-cover conditions in subsequent winters will strengthen these impacts," they wrote, and are also likely to lead to profound changes further afield, including in the tropics and the Northern Hemisphere.
What to watch now is whether low-ice winters recur in the Southern Ocean, since the study ties the strongest effects to that repetition.
Citazioni salienti
Repeated low ice-cover conditions in subsequent winters will strengthen these impacts and are also likely to lead to profound changes further afield, including the tropics and the Northern Hemisphere.— Study authors, Nature
Vuoi la storia completa?
Leggi l'originale su Raw Story ↗
Science & Space