zpostcode
Antarctic ice hole the size of Switzerland keeps cracking open. Now scientists finally know why.
Jul 18, 2025 8:00 PM

Scientists have finally discovered what's causing a Switzerland-size hole to repeatedly open up in Antarctica's sea ice.

Researchers first spotted the hole, called the Maud Rise polynya, in 1974 and 1976 in Antarctica's Weddell Sea, and since then it has reappeared fleetingly and sporadically opening up in different sizes but in the same place, then sometimes not at all for years. This left scientists puzzled as to the exact conditions needed for the hole to form.

In 2016 and 2017, a huge 309,000 square mile (80,000 square kilometers) opened up for several weeks during both winters, enabling scientists to get a closer look at the phenomenon and finally solve the 50-year mystery. They reported their findings Wednesday (May 1) in the journal Science Advances.

"2017 was the first time that we've had such a large and long-lived polynya in the Weddell Sea since the 1970s," lead author Aditya Narayanan, a postdoctoral researcher at the University of Southampton in England, said in a statement.

When summer turns to winter in Antarctica, sea ice expands from its minimum of around 1 million square miles (3 million square km) to 7 million square miles (18 million square km), covering 4% of Earth's surface in irregular, porcelain-white tiles.

Most of this sea ice grows during the weeks-long polar night on the floating ice shelf that wraps around the continent. Holes in this ice, called polynyas, form when strong winds from inland push the tiles apart.

Related: 'Unprecedented,' 'Gobsmacked', 'Unbelievable': Changes in Antarctica's sea ice could have dramatic impacts, says climate scientist Edward Doddridge

This cold wind also freezes more seawater inside the polynyas, adding extra chunks to the sheet of pack ice.

But in the open ocean and away from these coastal winds, where the Maud Rise polynya forms, holes in the sea ice are much less likely to develop. This, along with a startling reduction in the overall ice extent across the Southern Ocean, led scientists to wonder what specific conditions could be causing the Maud Rise polynya to form.

Antarctic sea ice decline

Deception Island, Antarctica.

(Image credit: karenfoleyphotography / Alamy Stock Photo)Antarctica's sea ice has been declining since 2016. What does that mean for Earth's climate?

Read more:

'2023 just blew everything off the charts': Antarctic sea ice hits troubling low for third consecutive year

Collapse of the West Antarctic ice sheet is 'unavoidable,' study finds

Antarctic sea ice reached 'record-smashing low' last month

To investigate the mystery, the scientists pored over data from satellites, autonomous floats and tagged marine mammals, as well as previous observations made by other researchers. They found that in 2016 and 2017, the Weddell Sea's circular ocean current, called the Weddell Gyre, was stronger than in other years, making it easier for underwater currents to bring salt and heat nearer to the surface.

The Maud Rise polynya is located near the Maud Rise, an underwater mountain. In 2016 and 2017, due to the stronger current, salt hovered around this seamount while wind blew over the surface, which created a corkscrew effect that dragged the saltier water around the submerged mountain to the surface. This salt then lowered the freezing point of the surface water, enabling the Maud Rise polynya to form and persist.

The new finding is important for understanding Antarctica and its broader impacts on the global ocean, according to the researchers. Climate change is already making winds from the southernmost continent more powerful, likely creating more polynyas in the future. Meanwhile, 40% of the global oceans waters finds their origins in the Antarctic coastline, making it vital in regulating regional climates across the planet.

"The imprint of polynyas can remain in the water for multiple years after they've formed. They can change how water moves around and how currents carry heat towards the continent," study co-author Sarah Gille, a professor of climatology at the University of California San Diego, said in the statement. "The dense waters that form here can spread across the global ocean."

Comments
Welcome to zpostcode comments! Please keep conversations courteous and on-topic. To fosterproductive and respectful conversations, you may see comments from our Community Managers.
Sign up to post
Sort by
Show More Comments
Recommend >
Osborn’s dwarf crocodile
  Also called: Congo dwarf crocodile (Show more) Osborn’s dwarf crocodile, (Osteolaemus osborni), small crocodile species that inhabits the tropical forests and wetlands of Africa’s Congo River basin. The geographic range of Osborn’s dwarf crocodile extends from southeastern Cameroon and southwestern Central African Republic southward to the Republic of the Congo, the Democratic Republic of the Congo, western Uganda, and northwestern...
Bill May
  In full: William Aaron May (Show more) Born: January 17, 1979, Syracuse, New York, U.S. (Show more) Bill May (born January 17, 1979, Syracuse, New York, U.S.) is an artistic swimmer who specializes in mixed duet performances. He has won numerous national and international competitions in spite of being excluded for much of his career from events in which men...
Old City of Jerusalem
  Related Places: Israel Jerusalem Gethsemane Mount of Olives (Show more) The Old City of Jerusalem, adorned with its ancient stone structures and garnished with gray and gold-plated domes, is a mosaic of the communities that through history have viewed the city as one of the most sacred meeting points between heaven and earth. For Jews, the city’s Mount Zion was...
Aam Aadmi Party
  Related People: Medha Patkar Arvind Kejriwal (Show more) Aam Aadmi Party (AAP), political party in India formed by Arvind Kejriwal in November 2012, in the wake of the 2011 anti-corruption movement in India. The Aam Aadmi Party (AAP; “Common Man’s Party”) is headquartered in New Delhi. It has served as the ruling party in the national capital territory of Delhi...
Information Recommendation
The Bear
  The Bear, American television dramedy about Carmen (“Carmy”) Berzatto (Jeremy Allen White), a fine-dining chef who returns to Chicago to help run his family’s Italian beef sandwich shop. Since its 2022 premiere, it has been among the most popular broadcast shows. It is produced by FX and appears on Hulu, becoming in its first season one of FX’s most-watched half-hour...
Fight Club
  Fight Club, American drama film, released in 1999, that was directed by David Fincher and adapted from Chuck Palahniuk’s 1996 novel of the same name. The film tells the story of an alienated office worker and a charismatic nihilist who start an underground club at which disaffected young men violently fight each other. Under the nihilist’s direction, club members begin...
Massive heat wave and a supercell thunderstorm caused deadly, baseball-sized hailstones to rain down on Spain
A heat wave fueled by climate change helped create deadly, record-breaking hail in Spain, a new study finds. The baseball-sized hail hit northeastern Spain in August 2022, injuring 67 people and killing a 20 month old girl. Videos of the storm show balls of ice up to 4.7 inches (12 centimeters) wide dropping from the sky, smashing car windows and...
12 Essential Brat Pack Flicks
  What defines a classic Brat Pack flick? Is it a plot involving teenage rebellion or angsty young adulthood? MTV-style film editing or a screenplay penned by John Hughes, the great bard of 1980s teen movies? Maybe it’s all about the cast. In 1985 journalist David Blum coined the term Brat Pack to describe a group of up-and-coming young actors. The...
Robert Anderson
  Born: June 14, 1805, Jefferson county, Kentucky, U.S. (Show more) Died: October 26, 1871, Nice, France (Show more) Robert Anderson (born June 14, 1805, Jefferson county, Kentucky, U.S.—died October 26, 1871, Nice, France) was a career U.S. Army officer who fought for the Union during the American Civil War. Anderson was the commander of the Federal garrison at Fort Sumter...
Boy in a Red Waistcoat
  Boy in a Red Waistcoat, an oil-on-canvas painting by Paul Cézanne created between 1888 and 1890, one of four oil paintings and two watercolors of this red-vested model. The work reflects the French painter’s distinctive style—a mix of Impressionism with Classicism and an intense intellectualism—that was so progressive for its time. Boy in a Red Waistcoat shows the artist’s preoccupation...
James McBride
  Born: September 11, 1957, Brooklyn, New York, U.S. (Show more) James McBride (born September 11, 1957, Brooklyn, New York, U.S.) is an American author and musician known for his acclaimed works of historical fiction and autobiography, including the best-selling memoir The Color of Water (1996) and the National Book Award-winning novel The Good Lord Bird (2013). McBride was the eighth...
The six criteria air pollutants
  Empowered by the Clean Air Act of 1970, the U.S. Environmental Protection Agency (EPA) quickly established air quality standards to protect public health and the environment. Focusing on six “criteria” air pollutants—sulfur dioxide, nitrogen dioxide, particulate matter, carbon monoxide, ozone, and lead—the resultant National Ambient Air Quality Standards became the centerpiece of air pollution regulations and required that all U.S....