While millions around the world grappled with extreme heat this month, a research station in Antarctica recorded Earth's coldest temperature since 2012.

The high-altitude research station, named Concordia, logged a low of minus 119.4 degrees Fahrenheit (minus 84.1 degrees Celsius) on July 18, according to data from the station.

Concordia is located in the interior of the Antarctic continent, which is currently in the dead of winter with no sunlight. Temperatures at the station regularly fall below minus 112 F (minus 80 C) this time of year ‪—‬ so the new reading isn't unprecedented, but it's still significant.

"Even here, where extreme cold is expected, temperatures below minus 84 C are remarkable and highlight how variable Antarctic weather can still be," Gabriele Carugati, the station leader at Concordia for Italy's National Antarctic Research Program (PNRA), told Live Science over a video call from the station.

The French Polar Institute Paul-Émile Victor, which runs Concordia with the PNRA, sent Live Science raw data from July 18, which showed the temperature dropping to minus 84.1 C twice, at 6:25 a.m. and 6:34 a.m. local time.

The extreme chill at Concordia stands in sharp contrast to the sweltering heat that many countries are currently experiencing. North America and Europe have been battling heat waves this summer, with Western Europe recording the hottest June on record. Meanwhile, wildfires are raging in Canada, the U.S., France, Spain and other countries.

Globally, average temperatures are going up as humans pump more heat-trapping greenhouse gases into the atmosphere. However, Earth's weather systems are complex, and climate change doesn't mean that everywhere gets hotter all of the time.

"Climate change describes the long-term global trends, while individual weather events can still [bring] exceptional cold," Carugati said. "Antarctica is influenced by complex atmospheric processes, so an extreme low temperature at one location does not contradict the broader picture of global warming."

"Astronauts of ice"

Concordia is considered the most remote and extreme research station in the world. Built on top of a 10,800-foot-thick (3,300 meters) ice cap, the station is used for a variety of purposes, including seismic observations, astronomy and the modeling of Earth's past climates, according to the French Polar Institute Paul-Émile Victor.

"Concordia is a special place because it sits at over 3,200 meters [10,500 feet] above sea level on the Antarctic Plateau, and more than 1,000 kilometers [600 miles] from the coast," Carugati said. "During winter, there is no sunlight for months, the atmosphere is extremely dry and stable, and under clear skies, heat continuously escapes to space because there are no clouds, allowing temperatures to fall to extraordinary levels."

Concordia's environment is so harsh and isolated that the station is also used to improve our understanding of the physical, mental and social challenges astronauts experience in space. Carugati noted that the only person at the station who is not researching the environment is a European Space Agency biomedical doctor, who is studying the researchers who work there, nicknamed "astronauts of ice."

Planes can't fly to Concordia once winter sets in, and it's around 370 miles (600 kilometers) from the nearest research station. That technically makes crews more isolated than astronauts on the International Space Station, which orbits about 250 miles (400 km) above Earth, according to the European Space Agency.

What is the coldest temperature ever recorded?

The coldest temperature ever recorded at Concordia was minus 120.5 F (minus 84.7 C), logged in the winter of 2010, according to the Italian Antarctic Meteo-Climatological Observatory. However, another high-altitude research station in East Antarctica has the all-time record for the coldest temperature ever recorded on Earth. Russia's Vostok weather station, the nearest station to Concordia, recorded a temp of minus 128.6 F (minus 89.2 C) in July 1983, according to the World Meteorological Organization.

Satellite data suggests that temperatures can drop as low as minus 144 F (98 C) in East Antarctica, according to a 2018 study published in the journal Geophysical Research Letters. However, even though Antarctica is the coldest and driest continent, it's not immune to global warming.

Major glaciers and the ice sheet they support are at risk in West Antarctica, with the Antarctic Peninsula — which extends out of the western side of the continent — experiencing the most rapid warming. A study published in February in the journal Frontiers in Environmental Science found that decisions made on greenhouse gas emissions today will determine how much the peninsula will change in the coming centuries, with sea ice, ice shelves and glaciers, along with the penguins that live on them, at risk of disappearing.

Concordia sits on the largest ice sheet on Earth. This sheet in East Antarctica is more stable than the smaller sheet of West Antarctica, but it is still vulnerable to rising temperatures. An unprecedented Antarctic winter heat wave in March 2024 saw temperatures near Concordia rise to a record high of 15.1 F (minus 9.4 C) ‪—‬ about 32 F (18 C) warmer than the previous March maximum. This East Antarctic heat wave was amplified by global warming, according to a study published in April in the journal npj Climate and Atmospheric Science.

Earth recently entered an El Niño, the warm phase of a multiyear natural climate pattern, which could bring unprecedented temperature extremes to an already-warming world. Carbon Brief, a U.K. based outlet that reports on climate news and policy, has predicted that 2026 is likely to be the second-warmest year on record, behind 2024, with the intensifying El Niño increasing the likelihood that 2027 will be the warmest year ever recorded.

For now, at Concordia, the researchers are continuing their work in the blistering cold of Antarctica's winter. Carugati noted that the latest extreme-temperature data will inform forecasts and long-term climate monitoring.

"Extreme observations like this help scientists better understand atmospheric processes and improve the climate models," he said.

The first dinosaur found in Antarctica belonged to a group that included the largest animals ever to walk the planet, a new study finds.

A backbone from the 82 million-year-old giant was discovered more than 40 years ago, but at the time, researchers assumed it came from an ancient marine reptile. Now a new study, published June 29 in the journal Acta Palaeontologica Polonica, has revealed that it was actually a titanosaur — the group of long-necked sauropods that included the largest land animals on record.

"At first glance this appears to be an unremarkable fossil, but it holds an important place in the history of Antarctic exploration as the first dinosaur fossil found on the continent," study first author Paul Barrett, a paleontologist at the Natural History Museum in London, said in a statement.

While this fossil now holds the record for the first dinosaur fossil found in Antarctica, other dinosaur fossils were identified on the continent after its discovery, so it's not the only known Antarctic dinosaur. In fact, researchers have identified a variety of dinosaurs on Antarctica, with another sauropod fossil identified as a titanosaur in 2011.

The newly identified dinosaur was around 20 to 23 feet (6 to 7 meters) long. That's very small compared with the largest-known titanosaurs, which could grow up to 123 feet (37.5 m) long. However, as the fossil is just a fragment of a vertebra, researchers are unable to narrow down which species the Antarctic titanosaur belonged to, and it's possible that the individual was only a juvenile when it died.

Mike Thomson, a British Antarctic Survey geologist, found the fossil during an expedition to James Ross Island in 1985. The island, which has been the site of multiple dinosaur discoveries, is located off the northeastern Antarctic Peninsula, south of the 600-mile-wide (965 kilometers) Drake Passage that separates South America from Antarctica.

Antarctica is well known for its icy landscapes, but when titanosaurs roamed Earth, the continent was still attached to South America and full of temperate forests. Antarctica's dinosaurs were so far south that they would have lived in constant twilight during the winter months, according to a news article published by the Natural History Museum.

The authors of the new study identified the dinosaur using high-resolution CT scans, which enabled them to look inside the fossil. Dating back to the Cretaceous period (143 million to 66 million years ago), the titanosaur lived in the last age of the non-avian dinosaurs, before an enormous asteroid hit what is now Mexico's Yucatan Peninsula 66 million years ago and wiped them out.

The Antarctic titanosaur helps researchers better understand how dinosaurs spread across Earth's southern continents, which at the time were combined into a supercontinent called Gondwana. The presence of titanosaurs on Antarctica suggests that they may have used Antarctica to travel from what is now South America to New Zealand.

Other dinosaurs identified on Antarctica include small herbivores, armored ankylosaurs and bipedal predators like Imperobator, which would have shared the forests with the newly identified titanosaur. While researchers are beginning to piece together Antarctica's ancient ecosystems, they still have a lot to learn about the dinosaurs that lived there.

"There are likely many more dinosaurs to be discovered on the continent," Barrett said. "As climate change causes ice to retreat we may indeed find further evidence of this past biodiversity."

A colossal chunk of sea ice roughly the size of Texas is missing from the west coast of Antarctica, and scientists fear it might never form again.

Antarctica is currently in winter, which runs from March to October on the southernmost continent. During the winter months, floating sea ice surrounding the continent typically grows, driving currents that regulate Earth's climate. But this year, there's a notable ice gap over the Bellingshausen Sea, on the western side of the Antarctic Peninsula.

Satellite observations have revealed that around 250,000 square miles (650,000 square kilometers) of sea ice hasn't formed yet, compared with the average amount of sea ice between 1991 and 2020, The Guardian reported last week. For comparison, the ice gap covers an area slightly larger than France or nearly the size of Texas.

Will Hobbs, a sea ice-ocean interaction scientist at the University of Tasmania, told The Guardian that he was "concerned" by the lack of sea ice and that it was "depressing." Hobbs noted that this year represents the third time in four years that the region's sea has been very low.

"I don't think we will see sea ice there any more," he said. "It's done."

Researchers still have a lot to learn about sea ice changes in Antarctica. Hobbs said that the sea ice loss was likely linked to changes in the ocean and that scientists are trying to determine whether global warming was a factor.

Sea ice has declined much more slowly in Antarctica than in the Arctic. But in recent years, scientists have been witnessing an astonishing change in the sea ice extent. One record low in 2016 was followed by another in 2022 and then a third in 2023.

Edward Doddridge, a physical oceanographer at the Institute for Marine and Antarctic Studies in Australia, told ABC News (Australia) that he was no longer surprised by sea ice loss.

"It's not good news, but it has become a pattern that we're expecting now," Doddridge said. "A warming world is going to have less sea ice."

The diminished winter sea ice is likely to have a variety of knock-on effects. For example, this area of sea ice normally provides important habitat for animals like krill and penguins. Sea ice also plays an important role in regulating the climate, including by driving key ocean currents, insulating the ocean from the sun, and protecting ice shelves at the mouths of glaciers.

Down the coast from the missing sea ice, researchers have warned that a key ice shelf is about to disintegrate from Antarctica's Thwaites Glacier — nicknamed the "Doomsday Glacier" because its collapse could raise sea levels by 2.1 feet (65 centimeters) in the coming centuries, flooding coastal communities worldwide. The ice shelf helps protect the mouth of the glacier by acting as a buttress, thereby restraining the flow of ice from the glacier into the sea.

Thwaites Glacier has been melting rapidly since the 1980s, which is part of a wider concern for the West Antarctic Ice Sheet that it helps to support. The collapse of such an ice sheet is considered one of the major environmental tipping points, or "points of no return," that humanity must avoid in the fight to rein in climate change.

Artificial intelligence (AI) has revealed hundreds of previously unknown earthquakes beneath the East Antarctic Ice Sheet, including some in an unexpected place: in the middle of a tectonic plate, far from a plate boundary.

The findings, published May 28 in the journal Science, reveal that Antarctica is more seismically active than previously thought and that new technologies can help to uncover hidden earthquakes in surprising locations.

In the new study, scientists used machine learning, a type of AI, to reanalyze seismic data taken from 49 seismic stations over the past two decades: one dataset from 2001 to 2004, and another from 2012 to 2015. The data revealed over 500 previously unrecognized earthquakes about 60 to 90 miles (100 to 150 kilometers) beneath David Glacier, which stretches nearly 700 miles (1,100 kilometers), bridging East and West Antarctica. This major outlet glacier drains about 4% of the East Antarctic Ice Sheet into the ocean, and its ice has thinned over the past several thousand years.

Earthquakes over 50 miles (80 km) deep are called intermediate-depth earthquakes. This type of earthquake is typically seen only at tectonic plate boundaries ‪—‬ specifically subduction zones, where one tectonic plate dives beneath another.

Yet the study showed that these earthquakes are happening in the middle of the tectonic plate, far from active plate boundaries.

"The earthquakes occur where the cold, rigid crust and upper mantle beneath East Antarctica meets warmer, softer rock beneath West Antarctica, and this contrast creates an abrupt change in tectonic strength," Long Ho, a University of Alabama geologist and first author of the new paper, told Live Science in an email. The detected earthquakes have magnitudes ranging from 1.6 to 3.5. The warm, buoyant material of the upper mantle extends beyond the edges of David Glacier from below, uplifting the edges of the nearby crust and bending them, and this concentrated stress causes the ground to shake, Ho explained.

It was surprising to find so many earthquakes at these depths, far from plate boundaries, Ho said, but similar earthquakes may be occurring in other geographic regions and going unnoticed given their small magnitudes. AI could help to identify those hidden quakes by reanalyzing past seismic data.

"As machine-learning tools continue to improve, they could reveal that deep, continental-interior earthquakes are more common than currently recognized," Ho said. "If so, the role of such events within the plate tectonics framework may need to be re-evaluated."

The results also show that Antarctica is more dynamic than previously thought. "Antarctica was [long] considered to largely lack earthquakes," Richard Alley, a glaciologist at Penn State who was not involved in the new paper, told Live Science in an email. "Now, we know that the apparent lack of earthquakes was really a lack of [tools] to listen to earthquakes." The data from this paper were collected between 2001 and 2004 and are now yielding new results as modern techniques have been developed to analyze the data, Alley said.

The detected earthquakes are not strong enough to threaten the overlying ice sheets or the Antarctic ecosystem, Ho said, so the research team is not concerned about that.

Next, Ho hopes to explore how the enormous weight of the Antarctic Ice Sheet might contribute to the location of earthquakes, and how changes in the ice sheet could affect underlying seismic activity.

It's still puzzling that seismic activity is concentrated at David Glacier rather than spread along the mountains in this region, Alley said, adding that the answer could be linked to the recent history of the ice sheet growing and shrinking, or to a longer history of the ice sheet eroding.

"I worry a lot about the ice sheet," Alley said, "and I hope work like this is continued and expanded, to help us understand the history and improve our understanding of possible futures."

How much do you know about Earth's frozen continent? Test your smarts with our Antarctica quiz!

Scientists have discovered a giant, fan-shaped structure that connects several well-known basins deep beneath the East Antarctic Ice Sheet — and it may have formed in the breakup of the ancient supercontinent Gondwana.

The feature is the product of a tectonic process known as distributed rotational extension, in which Earth's crust deforms outward from a fixed, central point, like fingers spreading out on a human hand. The gaps between the "fingers" in East Antarctica are triangular basins that were previously described but not recorded as belonging to a single system, researchers reported in a new study.

"Rotational extension is known from other tectonic settings, but recognizing a feature of this scale, hidden beneath the East Antarctic Ice Sheet, is quite remarkable," first author Egidio Armadillo, an associate professor and researcher in the Applied Geophysics Laboratory at the University of Genoa in Italy, told Live Science in an email. "If our interpretation is correct, this may be one of the largest and clearest examples of distributed rotational extension yet recognized in continental crust."

The discovery began with the simple observation that many buried basins in East Antarctica seem to radiate from the same place. From there, Armadillo and his colleagues examined the region's subglacial landscape and geology, as well as gravitational, magnetic and seismic data. They also used models to simulate the formation of the structure, which they named the East Antarctic Fan-Shaped Basin Province.

The results, published June 3 in the journal Nature Geoscience, support the idea that some of East Antarctica's best-known features — including the Wilkes and Aurora basins and the basin that hosts Lake Vostok, the largest known subglacial lake on Earth — were formed by distributed rotational extension. But it's unclear exactly when this happened, Armadillo said.

"The structure may have developed in more than one phase," he said. "However, we think it is likely connected to the long tectonic evolution that preceded and accompanied the breakup of Gondwana, especially the separation between Antarctica and Australia."

Gondwana splintered around 180 million years ago, creating the landmasses and continents we know today. The split between Antarctica and Australia occurred roughly 70 million years ago, toward the end of the Cretaceous period (145 million to 66 million years ago). The East Antarctic Fan-Shaped Basin Province may have facilitated this late separation by weakening a zone to the north of the province that eventually tore apart, but the province may have continued to fan out after Antarctica and Australia broke apart, Armadillo said.

The precise mechanism that drove East Antarctica's distributed rotational extension remains unknown. "In my view, this is one of the most exciting aspects of the study: it does not close the problem, but opens a new research direction," Armadillo said.

Overall, the results suggest East Antarctica has a much more dynamic tectonic history than scientists previously thought. "East Antarctica is often regarded as an old, cold and relatively stable cratonic [ancient and deeply rooted] region," Armadillo said. "In our model, the formation of the fan-shaped basin province strongly influences the surrounding landscape."

The structure opened several enormous basins that are now concealed under more than 1.8 miles (3 kilometers) of ice. To the west, the structure's formation may have contributed to the uplift of the Gamburtsev Mountains, which are similar to the European Alps in scale and shape but completely buried in ice. And to the east, the spreading of the "fingers" likely helped rotate and break up the Transantarctic Mountains, which divide East and West Antarctica, Armadillo said.

"The main message is that a large part of East Antarctica may not simply be a collection of separate subglacial basins, but a coherent tectonic province produced by a continent-scale deformation process," he said. "At the same time, our model is a hypothesis that can and should be tested further. In particular, better constraints on the timing of deformation will be essential."

The discovery could shed light on how the East Antarctic Ice Sheet will respond to climate change, because tectonic processes influence the paths followed by glaciers and ice streams when they melt. However, the broader significance of the findings is that Antarctica still conceals many geological secrets, Armadillo said.

"More than 99% of the bedrock is hidden beneath the ice, so integrating subglacial topography, gravity, magnetics, crustal structure and ice-sheet observations is essential," he noted.

Antarctica quiz: Test your knowledge on Earth's frozen continent

Antarctica's "Doomsday Glacier" is about to lose an ice shelf that protects it from warming ocean waters, which could have devastating long-term consequences for hundreds of millions of people affected by rising sea levels.

The already-melting Thwaites Glacier is nicknamed the "Doomsday Glacier" because if it totally collapses, global sea levels would rise by 26 inches (65 centimeters) and flood coastal communities. Rising sea levels are already threatening the residents of major cities in the U.S. and throughout the world, including New York, Boston, San Francisco and Miami.

Researchers don't expect the Florida-size glacier to collapse anytime soon, but Thwaites' eastern ice shelf is breaking away, which will likely accelerate the glacier's demise. The ice shelf has acted as a floating support structure, or buttress, slowing the flow of ice from the glacier, which is grounded on the Antarctic continent.

The shelf's breakup is "very likely to happen sometime this year," said Robert Larter, a marine geophysicist at the British Antarctic Survey (BAS), who announced that the BAS had already written the ice shelf's "obituary."

To discuss what the loss of the ice shelf spells for the glacier and coastal communities, Live Science spoke with Larter, who runs the U.K. arm of the science coordination office at the International Thwaites Glacier Collaboration (ITGC), where U.S and U.K. research agencies have investigated the glacier's complex and rapidly changing environment. Here's what he had to say.

Patrick Pester: What is happening to Thwaites Glacier?

Robert Larter: The last bit of ice shelf in front of the glacier is poised to disintegrate. We don't know quite how this ice shelf is going to break up, but it's definitely going to go. It's tearing away from the glacier at the moment, and its internal structure is getting more and more fragile. You can see the fractures and rifts growing in sequences of satellite images.

PP: What happens when the shelf breaks free?

RL: That is the big question. What we have seen over the last few years, as the ice shelf's structure becomes weaker, is that an area of the grounded ice has started to flow faster — an area where glacier ice is flowing into the ice shelf. So this shows that it was doing something to restrain the flow of the ice.

PP: Are warming oceans to blame for the undermining of the shelf?

RL: Yes, we're pretty sure of that. It's clear that it is warm ocean water that has done the damage, and there was a change in the delivery of this water sometime in the middle of the 20th century that has set off the current phase of ice loss and grounding zone retreats.

It's more the circulation of the water than the warming. The source of the water is several hundred meters deep in the Southern Ocean. There is a huge body of relatively warm water at depth in the Southern Ocean, and it's when this gets onto the continental shelf and gets to the front of the glaciers that it starts to do the damage.

PP: And is it humans' fault?

RL: There is a lot of work going on to try to establish that. But yeah, indications are that it is caused by human-forced climate change.

So, the circulation in the Southern Ocean is mainly driven by surface winds, and what we know has happened is that there have been changes in the wind patterns that drive this Southern Ocean circulation. There is an active scientific debate about exactly how this works, but it seems pretty clear that in some way, the changes to the Southern Hemisphere westerly winds are what is driving warm water onto the continent. And those wind changes are part of the wider pattern of climate change that we're seeing.

PP: Do you think the "Doomsday Glacier" nickname is appropriate?

RL: I mean, it's got us a lot of media attention. Initially, we resisted it. We didn't want to adopt that name because it kind of prejudges the conclusions of what we were trying to establish. But the collaboration started in 2018 ‪—‬ so eight years ago ‪—‬ and in light of the eight years of research results that are now coming in, I increasingly think it is appropriate. I think, overall, our results point to that, eventually, the Thwaites Glacier will be lost.

The time frame is still the big open research question. Most of us who are working on it are convinced that the retreat is not going to stop, but there is still a lot to work on to predict more accurately how long that is going to take. There's a whole range of ice sheet computer models that give a range of predictions. So I don't think anybody can state with a very high confidence what the rate of ice loss will be over the next century or two.

PP: What's the human and environmental impact of this accelerated ice loss around the world?

RL: This is a difficult thing to communicate because we're still at the level of talking of sea level rise changes of a few millimeters a year. So the current overall rate is 4 or 4 and a half millimeters [0.16 to 0.18 inches] a year of global mean sea level rise, and if you add an extra millimeter, it's difficult to get people excited about that.

But really, the important thing that we need to get across is that a small rise in sea level has a really disproportionate effect when you look forward a decade or two to the risks of coastal flooding in many areas. You don't need a lot of sea level rise, just a meter or two, to turn your once-a-century coastal flooding event into a once-a-decade or even an annual event.

So, although we're talking millimeters a year, centimeters a decade, maybe a few tens of centimeters over a century — and that's if it doesn't accelerate — those sorts of rates of sea level rise within a few decades are going to present us with major problems. They're presenting coastal cities with major infrastructure decisions about how they manage their defense, which is why we need to do that research to get a better idea of how fast Antarctica, Greenland, etc., are going to contribute to global sea level.

PP: Is there anything else you'd like to add that we haven't covered?

RL: I think it's incredibly important to explain what an ice shelf is and to make clear that an ice shelf is not the glacier. And in fact, what we're talking about here in terms of some of the ice shelves around Antarctica, it's a relatively small ice shelf. The glacier is a couple of orders of magnitude larger in area than the ice shelf, but it is going to be a significant, very visible change that you can see in satellite images.

As this ice shelf does break up, which I think is very likely to happen sometime within this year, we're going to see this ice shelf really move away and maybe totally fragment. That's going to be quite a spectacular event when you look at the sequence of satellite images. And then it's going to be very interesting to see how the glacier responds to that.

It is increasingly looking like "Doomsday Glacier" is a good name. The glacier is doomed. And the rate at which we're losing it is going to increase, I think, but it's not going to happen in the next few decades.

PP: That's good. In the broader scheme of climate and environmental news, that's something, I suppose.

RL: Yeah, but if we're right that it's doomed, we're committed to that much sea level rise. Even if we get to net zero [emissions] at 2050, this glacier is going to go. It is going to add 65 centimeters [26 inches] to sea level rise, which is a large commitment and will be something that's difficult to deal with in many places around the world.

And probably, loss of this glacier destabilizes other marine-based parts of the West Antarctic Ice Sheet, because the problem and the reason that this area is so unstable is that virtually the whole glacier is sitting on a bed that's a long way below sea level, and so are the neighboring glaciers.

So this instability is not going to stop when you've removed Thwaites Glacier. There's probably a total commitment in the West Antarctic Ice Sheet of more than 3 meters [9.8 feet] to sea level. It won't be our generation that has to deal with that.

Editor's note: This interview has been edited and condensed for clarity.

A vital ice shelf is about to break away from Antarctica's "Doomsday Glacier," further destabilizing one of the world's largest and most vulnerable glaciers.

The Thwaites Glacier is nicknamed the "Doomsday Glacier" because its collapse would send so much ice into the Southern Ocean that global sea levels would rise by 2.1 feet (65 centimeters or 26 inches), flooding coastal communities worldwide. This collapse could take centuries, but there is an imminent threat to Thwaites' eastern ice shelf, which will likely accelerate the glacier's demise.

Researchers say that satellite images reveal that the Thwaites eastern ice shelf is about to detach from the glacier, New Scientist reported last week. While the glacier sits on land, the ice shelf is a floating body of ice that is attached to the glacier's mouth. Researchers still have a lot to learn about the glacier, but this shelf acts as a buttress, restraining the flow of ice from the glacier into the sea.

Robert Larter, a marine geophysicist at the British Antarctic Survey, said that the ice shelf is very likely to break up in 2026. Larter runs the U.K. arm of the science coordination office at the International Thwaites Glacier Collaboration, where U.S and U.K. research agencies have investigated the glacier's complex and rapidly changing environment

"The last bit of ice shelf in front of the glacier is poised to disintegrate," Larter told Live Science in an interview. "We don't know quite how this ice shelf is going to break up, but it's definitely going to go."

Around the size of Florida, Thwaites Glacier is the largest glacier in West Antarctica. The gigantic river of ice is more than 6,500 feet (2,000 meters) thick in some parts and 75 miles (120 kilometers) across — making it Earth's widest glacier.

The glacier has been melting rapidly since the 1980s, losing hundreds of billions of tons of ice. That's due to relatively warm ocean water flowing underneath the ice shelf and melting the glacier at its base, where ice sits on ground that's below sea level. The glacier has retreated around 12.4 miles (20 km) since 1992.

Modeling the demise of massive glaciers is a complex task, making it hard to put an exact date on when Thwaites Glacier will finally collapse. However, a study published March 9 in the journal Geophysical Research Letters found that the glacier could be losing 180 billion to 200 billion tons of ice per year by 2067.

Thwaites Glacier's slow collapse is part of a wider concern among scientists for the future of the West Antarctic ice sheet. Thwaites is a key pillar of the ice sheet, protecting other ice from slipping into the ocean. If the whole ice sheet were to go, sea levels would rise by 10.8 feet (3.3 m), according to the British Antarctic Survey. The collapse of ice sheets like this one are considered tipping points, or "points of no return," in the fight against climate change — meaning that once they are crossed, they bring about permanent changes that cannot be reversed for many thousands of years.

The Thwaites eastern ice shelf is fracturing where the shelf is held in place by a ridge on the ocean floor, and at the mouth of the glacier. Larter said that movement on the western side of the shelf, where the ice is breaking away, has approximately doubled over the last eight months.

Much like other Antarctic sea ice — and the glacier itself — this shelf is undermined by warmer, saltier water being forced up from deep below the surface of the Southern Ocean. Larter noted that it's more about the circulation of water than warming, but indications are that human-driven climate change is ultimately to blame.

"There is an active scientific debate about exactly how this works, but it seems pretty clear that in some way, the changes to the Southern Hemisphere westerly winds are what is driving warm water onto the continent," Larter said. "And those wind changes are part of the wider pattern of climate change that we're seeing."

Antarctica's sea ice started shrinking dramatically in 2015 after resisting global warming for decades, and researchers now know why.

A study published May 8 in the journal Science Advances reveals that Antarctic sea ice succumbed to strong winds that disturbed the Southern Ocean's layers, replacing cold and relatively fresh surface water with warmer, saltier water that caused some initial melting. As sea ice declined over the years and reflected less sunlight back to space, the ocean absorbed more heat, thus accelerating the loss way beyond what scientists were expecting.

The research identified three phases of Antarctic sea ice decline between 2013 and 2023. Previous data shows that sea ice extent hit a record low in February 2023 and that Antarctica was missing a chunk of ice bigger than Western Europe at winter's peak in July of the same year. The continent has not recovered since, with sea ice extent reaching another near record low in 2024 and remaining below the 1981-to-2010 average in 2025 and early 2026.

"The system is behaving in a different manner," study first author Aditya Narayanan, a physical oceanographer at the University of New South Wales in Australia and the University of Southampton in the U.K., told Live Science. "Obviously, something has changed."

To pinpoint what caused such sudden and rapid sea ice loss, Narayanan and his colleagues used a model and observations from satellites and sensors in the Southern Ocean. The researchers fed the real-life data into the model to constrain its output and bring the results closer to what scientists have watched unfold in Antarctica since 2015.

"The model we used is sort of a hybrid," Narayanan said. "It digests all of the observational products that we feed into it, and it also runs a numerical model, much like a climate model."

Phase 1: Westerly winds push surface waters north

As in real life, sea ice in the model expanded between 2013 and 2015. The Southern Ocean's surface was cold and relatively fresh during this period, but the simulation showed that a warm, salty layer deep beneath the surface was rising and eroding the winter water layer — a thick band of frigid water that, up until recently, served as a barrier to protect surface waters from warmer waters below.

Study co-author Theo Spira, a researcher in the Alfred Wegener Institute at the Helmholtz Center for Polar and Marine Research in Germany, reported in a March paper that the winter water layer has been thinning since 2005. That's because the Southern Hemisphere westerlies, which are strong winds that blow eastward around Antarctica, picked up due to the ozone hole above the continent, Narayanan said. The ozone hole strengthened the Antarctic polar vortex, which, in turn, intensified the westerlies.

Strong westerly winds around Antarctica displace surface waters northward, causing the water below to rise to replace them. This process unfolds very slowly, and the immediate response of the Southern Ocean to stronger winds in the 2000s and early 2010s was to grow more sea ice, because cold fresh water reached farther out along the margins of the frozen continent, Narayanan said.

"The hypothesis already existed in the literature that when you strengthen the winds, you get a response from the ocean on two different timescales," he said. "The immediate response is to see a growth in the sea ice coverage. But then, if you keep this going for a few years or up to a few decades, you start to get this slower response. It takes a while, but what happens is, the heat that's deeper in the ocean starts to rise up, simply because you're moving waters away."

Phase 2: Warm water rises and initiates melting

In 2015, the westerlies became even stronger, accelerating the movement of surface waters away from Antarctica and the rise of warmer, saltier layers to replace them. By this point, the ozone hole was recovering, but the atmosphere was warming due to human greenhouse gas emissions, which have the same effect of intensifying the westerlies, Narayanan said.

The model showed that warm, salty water penetrated the winter water layer and reached the surface, where the water underwent turbulent mixing due to the powerful winds. "After 2015, you clearly see enhanced mixing from below of heat and salt," Narayanan said. "Our study bears it out that the initiator of sea ice loss was this heat from below."

The salt weakened the layers that naturally occur in the Southern Ocean, meaning more heat and salt could migrate upward after the initial breach in 2015. This feedback mechanism sped up sea ice melt, particularly in East Antarctica, the study found.

Phase 3: Heat and salt trigger feedback loops

By 2018, so much sea ice had melted in Antarctica that the decline became a self-reinforcing process.

Sea ice loss reduced the amount of sunlight that was reflected into space by this white surface and increased the amount of heat absorbed by the Southern Ocean, especially in the summer. This delayed the growth of sea ice every subsequent fall, as the ocean had to transfer its excess heat to the atmosphere before it could produce sea ice. The later in the year that sea ice forms, the smaller sea ice extent becomes and the more heat the ocean absorbs, Narayanan said.

Sea ice is a source of fresh water when it melts in the summer, and previously, this helped to keep the Southern Ocean's surface cold and relatively fresh. But the less sea ice grows in fall and winter, the less fresh water is available to maintain the Southern Ocean's natural layers. "A saltier upper ocean means you can keep the vertical layering weak and you keep the vertical mixing going," Narayanan said.

This is what led to the record-low sea ice extent observed in 2023. And if humans keep pumping greenhouse gases into the atmosphere, there is little hope that Antarctica will recover, because our emissions are strengthening the westerlies and warming the atmosphere, Narayanan said.

"If we keep emissions going, we will see sea ice receding farther and farther out to the continent, but I'm not sure how quick that change is going to be," he said.

An uncertain future

Climate change is expected to boost precipitation over the Southern Ocean, which could counteract the westerlies' impact on sea ice. More melting of Antarctic glaciers and ice sheets could also restore the ocean's layers. Therefore, it remains unclear if Antarctica has reached a tipping point, Narayanan said.

"Is it a collapse? Not yet," he said; but currently, the frozen continent is completely out of whack and behaving like a "new system."

Antarctic sea ice exhibits considerable year-to-year change, so it may be an oversimplification to think about this system in terms of a tipping point, said Ariaan Purich, a senior lecturer and climatologist at Monash University in Australia who was not involved in the research.

"For Antarctic sea ice, rather than thinking of tipping, we can think of abrupt change," Purich told Live Science in an email. "There is building evidence that Antarctic sea ice has undergone an abrupt change to a new low coverage state. A big question remains over whether sea ice will stay relatively stable in this state, or continue to decline over the coming years."

The Southern Ocean has absorbed roughly 75% of the excess heat in the atmosphere over the past 50 years, and sea ice plays a major role in this storage. When sea ice forms, it releases salt that creates dense, northward-flowing currents, which carry heat and carbon from the atmosphere to the depths of the ocean.

As sea ice shrinks, salt becomes less concentrated in the Southern Ocean, thus preventing the water from sinking and storing heat and carbon at depth. "That's something that's concerning, if it [sea ice loss] changes the balance, and if it reduces the ability of the Southern Ocean to store heat and carbon at depth," Narayanan said.

Plenty of organisms also rely on sea ice to survive, including krill, dolphins, whales and penguins. Sea ice loss has already impacted the ecosystem in Antarctica through mass die-offs in penguin colonies.

The sudden switch from high sea ice extent in the 2000s and early 2010s to record-low extent in the mid 2020s "is one of the largest present-day climatic shifts in the Earth system," Narayanan and his colleagues wrote in the study. A cascade of undesirable events could come from this, including less carbon and heat storage, more global warming, ecosystem degradation, and exposure of Antarctic ice shelves to warmer water as sea ice disappears.

Editor's Note: This article was updated at 5:20 a.m. ET on May 19 to include comments from Ariaan Purich, who was not involved in the new study.

Antarctica quiz: Test your knowledge on Earth's frozen continent

Don Juan Pond is a lake in Antarctica's extremely cold McMurdo Dry Valleys region that has a salinity above 40%, making it one of the saltiest bodies of water on Earth. The pond contains so much salt, it has a syrupy consistency that never freezes, even though temperatures in the Dry Valleys often fall to minus 58 degrees Fahrenheit (minus 50 degrees Celsius).

Don Juan Pond is 4 inches (10 centimeters) deep and slightly smaller than the total area of six football fields. It is named after two U.S. Navy helicopter pilots, Donald Roe and John Hickey, who spotted the pond during a reconnaissance expedition in 1961. There are other lakes in the Dry Valleys ‪—‬ but none are as salty as Don Juan Pond, so they stay frozen solid for most of the year.

Scientists are fascinated by Don Juan Pond because the harsh conditions in the McMurdo Dry Valleys resemble those on Mars, according to NASA. The Red Planet is bitterly cold and dry, rich in a variety of salts, and potentially hosts water. There is evidence for microbial life near Don Juan Pond, and it's possible that some organisms survive in the brine. If life can persist in the Dry Valleys, then life may exist, or may have once existed, in hypersaline features on Mars.

Don Juan Pond has elevated levels of calcium chloride, which is a highly soluble salt that lowers the pond's freezing temperature by keeping apart water molecules that would otherwise bond to make ice crystals. At 40% salinity, Don Juan Pond is much saltier than the Dead Sea, which has a salinity of 34%, and it is 12 times saltier than Earth's oceans, which have a salinity of 3.5%.

Scientists have been studying Don Juan Pond for more than 60 years, but they still aren't sure where the water and calcium chloride come from. Since the lake's discovery, the dominant hypothesis has been that Don Juan Pond is fed by groundwater bubbling to the surface. But in a 2013 study, Brown University geologists reported that the water is moisture from the atmosphere that is trapped by salts in the soil and eventually trickles down into the Upper Wright Valley, where Don Juan Pond is located.

The researchers took thousands of time-lapse photographs of the pond and the Upper Wright Valley's steep slopes. The images showed dark streaks near Don Juan Pond that the team argued were wet, salt-rich sediments funneling water toward the pond. Similar streaks, known as recurring slope linear features, occur on Mars' surface, hinting that a corresponding process may have once taken place on the Red Planet.

However, this hypothesis was contradicted by a 2017 study that revived the groundwater theory. That research, which was based on model simulations, indicated that the only way Don Juan Pond could have acquired its unique chemical makeup is if the water source were a deep groundwater system.

"If we accept that the deep groundwater theory is true, then what we're seeing could be part of a bigger process that involves quite an extensive aquifer," first author Jonathan Toner, an astrobiologist and research assistant professor at the University of Washington, said in a statement in 2017. "When thinking about the implications for a similar environment on Mars, that's much more exciting than just a localized surface phenomenon."

However, the source of water at Don Juan Pond is still debated.

Discover more incredible places, where we highlight the fantastic history and science behind some of the most dramatic landscapes on Earth.

Something strange has been swirling in the waters around Antarctica. From the 1970s until a decade ago, the floating sea ice that radiates from the continent had been expanding, even with climate change already in full swing. Then, in 2016, it suddenly and dramatically contracted — and has yet to recover — as rising global temperatures seemed to catch up with the Southern Ocean. Far from being just a local issue, the loss of sea ice has huge implications for Antarctica's vast ice sheet, which would drive sea levels up 190 feet if it disappeared.

Now, scientists say they've identified what's behind this rise and sudden fall, thanks to an assist from deep-diving robots. It all comes down to salinity, winds, and churn. "One of the key takeaways from the study is that the ocean plays a huge role in sort of modulating how sea ice can vary from year to year, decade to decade," said Earle Wilson, a polar oceanographer at Stanford University and lead author of a new paper describing the research.

Doing the grunt work here was a network of data-gathering machines known as Argo floats. Torpedo-shaped and about the size of a human, they sink thousands of feet, sampling things like temperature and salinity, before popping back up to the surface and transmitting all that data to a satellite. Because they float passively, the instruments could for years gather data about how conditions were changing.

Now, forget about robots and think about swimming in a lake. When you dive, you're hit by a sudden rush of cold water. That's because the sun warms the surface, while the depths stay cool. This also happens in the world's oceans, though obviously the cold water goes much deeper.

The opposite happens in the waters around Antarctica. Because it's so cold down there, the air cools the ocean surface, while warmer waters swirl below. (Argo robots could detect this in fine detail as they ascended and descended.) With warmer liquid kept away from the surface, more sea ice can form.

As sea ice expanded in the decades before 2016, increased precipitation made surface waters fresher, in contrast to saltier waters below, resulting in stratification. (The saltier a liquid is, the denser it becomes.) This trapped the warmth in the depths, allowing it to build up.

Then the atmosphere played yet another trick, as winds intensified and shifted. This pushed surface waters away from Antarctica and churned up that deeper warmth. "What we witnessed was basically this very violent release of all that pent up heat from below that we linked to the sea ice decline," Wilson said.

This bluster was likely driven at least in part by climate change: As the planet warms, the atmosphere develops temperature gradients, which strengthen winds and change their patterns. Scientists, though, are still working out how much of this shift might be due to "natural variability," or what might happen anyway if humans hadn't released so much carbon since the Industrial Revolution.

Either way, the system shifted around 2016. Beyond bringing up warm waters, all that wind may have broken up the ice, both by pushing blocks together and by creating waves. "Recent research has shown that both atmospheric and oceanic warming is likely contributing to the sudden change in Antarctic sea-ice extent since 2016, and this paper helps to further develop the point that deeper ocean warmth is a significant player," said Zachary Labe, a climate scientist at the research group Climate Central who studies Antarctic ice but wasn't involved in the paper.

As sea ice has declined, it has imperiled far more ice elsewhere. The Antarctic ice sheet that rests on land is bolstered by ice shelves that float along the coast. These essential supports are already in serious trouble as warming seas and violent underwater storms erode their bellies, weakening them. If they also lose the sea ice floating around them, they lose a significant buffer, as the floating chunks absorb wave energy. In addition, a healthy amount of sea ice is quite bright, meaning it reflects a bunch of the sun’s warmth into space, reducing local temperatures. Because the ice shelves hold back the ice sheet, losing them would mean an accelerated decline of an extraordinary amount of frozen water sitting on the continent.

While the Argo floats provided invaluable data, scientists are scrambling to get still more measurements. "Overall, we need more international support to continue building observing networks across the Antarctic polar region, both for oceanic and atmospheric monitoring," Labe said. "This is critical given the rapid changes we are beginning to observe in this part of the world in a warming climate, with potentially significant consequences for global sea level rise."

The big question now is whether we're witnessing a permanent state of low sea ice, or whether atmospheric and oceanic conditions might swing back enough to encourage years of growth. The promise of this new research is that it will help researchers refine their models to predict how much the waters around Antarctica might change, and how quickly. Perhaps sea ice will see years of sharp decline, followed by years of growth. "But the long-term, multidecade trend will be negative," Wilson said. "That would be my guess, but we don't know for sure."

This story was originally published by Grist. Sign up for Grist’'sweekly newsletter here.

A warming climate could expose a Pennsylvania-sized chunk of ice-free land in Antarctica by 2300, which could drastically reshape Antarctic geopolitics as well as the continent's geography.

A study published in Nature Climate Change is the first to incorporate glacial isostatic adjustment — how land beneath heavy ice sheets uplifts after the ice retreats — into projections of ice-free land emergence in Antarctica. The results reveal that climate change could expose potentially valuable mineral resources that may spur renegotiations of the international treaties that currently govern Antarctica.

As more ice-free land emerges in Antarctica, said Erica Lucas, a geophysicist at the University of California, Santa Cruz, countries may become more interested in its mineral resource potential. Lucas is the lead author of the new study.

Rebounding resources

Beneath Antarctica's ice sheet lies a varied landscape with mountains, canyons, valleys, and even volcanoes. As the climate warms, the ice sheet is slowly retreating, uncovering some of that land.

But until now, projections of ice-free land emergence had considered only changes to ice margins — how the spatial extent of ice cover will shift. Simulations of Antarctica's future accessible land hadn't considered how land would uplift once uncovered by ice or how different sea level scenarios would affect the amount of ice-free land that might emerge.

Lucas's projections included these factors by incorporating expected sea level changes, information about the thickness of Earth's lithosphere, and estimates of how the absence of the gravitational pull of an ice sheet would affect land uplift.

The study estimated that 120,610 square kilometers (46,578 square miles), 36,381 square kilometers (14,047 square miles), and 149 square kilometers (58 square miles) of land would emerge by 2300 under high–, medium–, and low–ice melt conditions, respectively. "We know we’ve had ice retreat and grounding line retreat over the past couple of decades," so the ranges of projected ice-free land emergence were not surprising, Lucas said.

South pole politics

Within the area that Lucas and the research team projected would be ice-free by 2300 lie known or suspected deposits of copper, gold, silver, iron, and platinum — critical minerals used in manufacturing and valuable metals in and of themselves. In particular, the study found the largest land emergence in Antarctica is likely to occur over territories claimed by Argentina, Chile, and the United Kingdom and contains a range of mineral deposits, including copper, gold, silver, and iron.

Currently, commercial mineral extraction is not allowed in Antarctica, though the Antarctic Treaty does allow for activities related to mineral resources if they are conducted strictly for scientific purposes.

If mineral resources become simpler to extract, countries with territorial claims in Antarctica would have an incentive to renegotiate those terms, the study's authors suggest. The first window for renegotiation is in 2048, when parties to the Antarctic Treaty are permitted to call for a review of the treaty's environmental protocol.

The authors suggest that these changes to Antarctic land could put pressure on the region's legal framework surrounding mineral resource activities. "That's a fair assessment," wrote Tim Stephens, a professor of international law at the University of Sydney Law School who was not involved in the new study, in an email. "However, the ice-free land emergence projected by the new study is unlikely to trigger a major change to Antarctic governance on its own," he wrote.

"The continent will still remain a very challenging environment for mineral resource extraction," he wrote, adding that the transformation of the Antarctic environment could also spur greater cooperation and focus on the environmental protection objectives of the Antarctic Treaty.

This article was originally published on Eos.org. Read the original article.

Antarctica could heat up 1.4 times faster than the rest of the Southern Hemisphere over the coming decades, which would lock in extreme sea-level rise and ravage polar ecosystems, a new modeling study shows.

This acceleration of warming in Antarctica relative to other regions, known as Antarctic amplification, would likely occur if global temperatures reached 3.6 degrees Fahrenheit (2 degrees Celsius) above preindustrial levels, according to the study. The world has already warmed by 2 F (1.1 C), and the pace at which new temperature records are being set is intensifying. If emissions stay around current levels, we will likely reach 3.6 F of warming around 2050 — but if emissions keep rising, we could hit that threshold around 2040.

The new research is among the first to find a clear sign of Antarctic amplification, which has been hard to detect due to the Southern Ocean's enormous capacity to absorb heat and the powerful circumpolar currents that isolate the frozen continent from rising temperatures. Yet most scientists think Antarctic amplification will happen, because amplification in the Arctic is already underway.

"For many years, Antarctica seemed isolated from the effects of increasing global temperatures," Ariaan Purich, a senior lecturer and climatologist at Monash University in Australia who was not involved in the research, told Live Science in an email. "In this new study, the authors propose that long-term surface warming of the ocean around Antarctica, projected by climate models over the coming century, leads to Antarctic amplification."

Arctic amplification has been documented for years, with temperatures in this region climbing about four times faster than the global average increase over the past five decades. The main mechanism driving Arctic amplification is the ice-albedo feedback, where the melting of snow and ice accelerates warming because water reflects less heat back to space. Where there once used to be reflective sea ice, there is now an ocean that absorbs more heat from sunlight. This causes more ice and snow to melt, in turn exposing even more heat-absorbing water.

Antarctica behaves differently, partly because swirling ocean and wind currents shield the continent from rising air and sea temperatures elsewhere in the world. Contrary to the Arctic, most of Antarctica experienced only gradual warming and no declines in sea ice until about a decade ago, Purich said.

But then, between 2014 and 2016, Antarctica lost as much sea ice as the Arctic had lost in four decades. The continent hasn't bounced back since, Purich said, with exceptionally low winter sea ice extent recorded in 2023, in particular.

"We're now seeing abrupt changes occurring in Antarctica, at very rapid rates," Purich said. "With low Antarctic sea ice coverage, there is now the potential for the ice-albedo feedback to start exacerbating warming of the southern high latitudes."

But scientists haven't observed this amplification signal directly yet. So, for the new study, researchers in China analyzed data from climate models to investigate whether Antarctic amplification could occur under a 3.6 F warming scenario. Using polar amplification simulations, along with models developed for the latest Intergovernmental Panel on Climate Change (IPCC) report, the researchers explored the impact of continued global warming on Antarctic temperatures.

Their findings — published Dec. 22, 2025, in the journal Geophysical Research Letters — suggest Antarctica will warm faster than the Southern Hemisphere as a whole under future climate conditions.

The researchers also discovered the main driver of Antarctic amplification: Unlike in the Arctic, where the ice-albedo feedback is a key driving force, Antarctica will warm mainly through accelerating heat release from the surrounding ocean.

Antarctic amplification may not have set in yet, but the effects of climate change have already arrived, Purich said. Over the past decade, scientists have observed drastic declines in Antarctic sea ice and catastrophic breeding failures in emperor penguins (Aptenodytes forsteri) due to melting.

"These things are happening now, and every fraction of warming that we can avoid matters," Purich said.

The new study is based on models, which, in the case of Antarctica, means the results may underplay future amplification, Purich said. Climate models are limited in their ability to predict certain warming mechanisms, and it's still unclear exactly how Antarctica's circumpolar currents will affect temperature changes.

"Together, this raises the possibility that the climate models may underestimate the potential and magnitude of Antarctic amplification to emerge over coming decades and centuries," Purich said.

Antarctica quiz: Test your knowledge on Earth's frozen continent

​​Antarctica, which is nearly four times the size of the United States, is almost entirely covered by a miles-thick layer of ice.

But the South Pole hasn't always been frozen. So when was the last time Antarctica was ice-free?

This ice cap formed relatively recently in geological terms, experts told Live Science. "I think most people would say 34 million years ago was when the ice sheet first formed in Antarctica," said Eric Wolff, a paleoclimatologist at the University of Cambridge. "[Previously] most of it would have been like northern Canada today — tundra and coniferous forest."

Global temperatures are a key factor influencing the extent of ice coverage. Around 50 million years ago, the world was about 25 degrees Fahrenheit (14 degrees Celsius) warmer than it is today, but temperatures steadily decreased over the following 16 million years. By 34 million years ago — a time period known as the Eocene-Oligocene boundary — the climate was 14.4 F (8 C) warmer than it is today.

But what triggered this temperature drop, and was that all it took for the ice sheets to form?

Related: Which is colder: The North or South Pole?

"There are two factors, and probably both were in play," Wolff told Live Science. "One of them is a change in the carbon dioxide concentration of the atmosphere, and the other is the movements of the continents and, in particular, the opening up of the Drake Passage," the strait between South America and Antarctica that connects the South Atlantic with the South Pacific.

The more carbon dioxide that's in the atmosphere, the more heat is trapped and the warmer the planet is.

From about 60 million to 50 million years ago, the carbon dioxide concentration in Earth's atmosphere was really high — somewhere around 1,000 to 2,000 parts per million, or between 2.5 to 5 times today's levels, said Tina van de Flierdt, a geochemist at Imperial College London.

"But we know that the CO2 in the atmosphere came down across that Eocene-Oligocene boundary," she told Live Science. This decrease in atmospheric CO2 would have been accompanied by a cooling of the global climate, she added, probably tipping Earth over a threshold and allowing ice sheets to form.

However, there was also likely localized cooling on the Antarctic continent due to plate tectonics, Wolff said. Around this time, South America and Antarctica finally separated, opening up what's now the Drake Passage.

"This led to what we call a circumpolar current — water going right around Antarctica in a circle," Wolff said. "This isolates Antarctica from the rest of the world and makes it much harder for warm air masses to get across the Southern Ocean and, therefore, makes Antarctica colder."

Plate tectonics also directly influenced carbon dioxide levels, he added. Rock weathering and volcanic activity are both part of the carbon cycle, so over thousands of years, geological processes can shift the balance of gases in the atmosphere.

Although some uncertainty remains, researchers are fairly confident about this transition 34 million years ago thanks to the chemical signatures in rock sediments. Oxygen atoms exist in two forms: oxygen-16 (common oxygen) and oxygen-18 (heavy oxygen). Continental ice contains a higher proportion of the lighter oxygen-16, meaning the oceans — and, therefore, the shells of small sea creatures — contain a higher percentage of oxygen-18 when ice sheets are bigger.

"By looking at the oxygen isotopes in the carbonate shells of small sea creatures in ocean sediments, you see a jump around 34 million years ago, which people take as being because the [lighter] oxygen isotope is going onto the continent of Antarctica," Wolff explained.

As for whether Antarctica could ever be ice-free again, "It's definitely possible, van de Flierdt said. "Planet Earth has done it before. Planet Earth could do it again." While it's unlikely that human activity will lead to the complete melting of the ice sheet, it's important we do everything possible to limit the loss of ice from the Antarctic now, she added. "It's in our hands to avoid the worst-case scenario," van de Flierdt said.

Editor's note: This story was originally published on Sept. 8, 2024.

While the new moon this Tuesday (Feb. 17) will pass without much fanfare in most of the world, something more exciting will be taking place over a sliver of Antarctica: a "ring of fire" solar eclipse, also known as an annular solar eclipse.

During an annular solar eclipse, the moon passes directly in front of the sun but appears too small in the sky to cover it completely. That’s because the moon is at its farthest point from Earth in its slightly elliptical orbit during these rare eclipses. On Feb. 17, 96% of the sun will be covered during the "ring of fire."

Observers within a narrow 383-mile-wide (616 kilometers) path will see a "ring of fire" — the glowing edge of the sun around the dark silhouette of the moon — for up to 2 minutes, 20 seconds.

However, few people will witness it. This eclipse is as remote as they come, with the eclipse's path passing over largely uninhabited terrain in the Antarctic interior.

"It's possible that only a few people will view this eclipse from within the annular zone," eclipse meteorologist Jay Anderson wrote on his website, Eclipsophile. "It's a challenge to reach, and there are only two inhabited locations within the annular shadow, neither of which is set up to welcome tourists. "At worst, a few dozen Russian researchers at Mirny and a small number of French/Italian inhabitants at Concordia [two research stations in Antarctica] will record the event for posterity."

An eclipse for scientists (and penguins)

At Mirny Station, on the Davis Sea coast, the "ring of fire" phase, called annularity, will last 1 minute, 52 seconds, according to Time and Date. Meanwhile, Concordia Station, which is jointly operated by France and Italy, will see the ring of fire for 2 minutes, 9 seconds. The latter location has a much better chance of clear skies, Time and Date adds.

The eclipse officially starts at 09:56 UTC (4:46 a.m. EST), when a partial eclipse will begin across Antarctica and parts of southeastern Africa. (Mozambique, Madagascar and Mauritius will see a 10% to 35% partial eclipse.) The annular phase takes place between 11:42 UTC and 12:41 UTC (6:42 to 7:42 a.m. EST), with the partial phases concluding by 14:27 UTC (2:27 p.m. EST).

Eclipses always come in pairs. With the alignment between the sun, the new moon and Earth precise enough to cause an annular solar eclipse on Feb. 17, a lunar eclipse is inevitable during the next new moon. On March 3, a total lunar eclipse will be visible from East Asia, Australia, New Zealand, parts of the Pacific Ocean and western North America.

The next annular solar eclipse will occur on Feb. 6, 2027, when a "ring of fire" will be visible for up to 7 minutes, 51 seconds from Chile, Argentina, Uruguay, Côte d'Ivoire, Ghana, Togo, Benin and Nigeria, according to Time and Date.

The world's formerly largest iceberg, A23a, has been transformed into a beautiful blob of stripy "blue mush," signaling its imminent demise, new satellite photos reveal. The dying ice mass, which until recently was three times larger than New York City, is one of the oldest bergs on record, now nearing its 40th birthday.

A23a is an oddity among icebergs. The megaberg, dubbed the "queen of icebergs," broke off from Antarctica's Filchner-Ronne Ice Sheet in the summer of 1986, but quickly became stuck in place when its submerged bottom caught on the seafloor. It remained trapped for most of the last four decades, barely shrinking in size due to its close proximity to its parent ice shelf. However, A23a finally broke free from its seafloor tether in 2020 and began drifting away from Antarctica.

Its subsequent journey has been eventful. First, the hefty ice mass was trapped again, this time in a massive ocean current, or gyre, which caused it to spin in place for months. Then, after breaking free from the vortex in December 2024, the dizzy berg made a beeline for the island of South Georgia, sparking fears among researchers that it would ground again and trigger a potential ecological disaster for the island's resident penguins. However, this worst-case scenario was avoided when A23a began to break apart in May 2025, shortly before reaching the island.

Since then, the largest remaining chunk of the iceberg has drifted further north into the South Atlantic Ocean, where warmer waters circulating down from South America are taking their toll.

New photos, captured on Dec. 26 by NASA's Terra satellite, reveal a completely unrecognizable version of A23a. The iceberg, which is now around a third of its original size, is shown covered with pools of blue water encircled by thick borders of white ice, dubbed "ramparts." In the image, A23a is also flanked by a pool of gray sludge, known as ice melange, which has likely leaked out from under the iceberg. It is also further surrounded by hundreds of smaller bergs that have broken off its edges.

The "blue mush" visible on A23a is made up of melt ponds, which form when surface ice loses its structural integrity, Ted Scambos, a climate scientist at the University of Colorado Boulder, said in a NASA statement. These ponds align into streaks, likely caused by the "weight of the water sitting inside cracks in the ice and forcing them open," Scambos added.

The cracks likely run parallel to grooves on the iceberg's underside, which were carved into the ice by centuries of movement over the ground while still attached to the Filchner-Ronne Ice Sheet, Walter Meier, a senior research scientist at the National Snow & Ice Data Center (NSIDC), said in the statement. "It's impressive that these striations still show up after so much time has passed," added Chris Shuman, a retired glaciologist formerly with the University of Maryland.

The vibrant striations may have already started to disappear, according to another photo, snapped on Dec. 27 by an unnamed astronaut onboard the International Space Station. This subsequent image shows a more uniform pool of blue water on the iceberg's surface (see below).

It is currently unclear how much of A23a remains or if it has already begun to disappear fully.

Due to its persistent massive size, A23a has repeatedly held the title of "world's largest iceberg" throughout its long lifespan.

It most recently regained the title in June 2023, when the previous largest iceberg, A-76A, broke apart; then, it lost the accolade again in September 2025, shortly after its encounter with South Georgia. (Some outlets have misreported that A23a remains the world's largest iceberg, likely due to an outdated page from Guinness World Records.)

The world's current largest iceberg is now D15A, which has a surface area of around 1,200 square miles (3,100 square kilometers), according to NSIDC, making it a few hundred square miles smaller than A23a at its peak.

For more incredible satellite photos and astronaut images, check out our Earth from space archives.

Glacial earthquakes are a special type of earthquake generated in cold, icy regions. First discovered in the northern hemisphere more than 20 years ago, these quakes occur when huge chunks of ice fall from glaciers into the sea.

Until now, only a very few have been found in the Antarctic. In a new study published in Geophysical Research Letters, I present evidence for hundreds of these quakes in Antarctica between 2010 and 2023, mostly at the ocean end of the Thwaites Glacier — the so-called Doomsday Glacier that could send sea levels rising rapidly if it were to collapse.

A recent discovery

A glacial earthquake is created when tall, thin icebergs fall off the end of a glacier into the ocean.

When these icebergs capsize, they clash violently with the “mother” glacier. The clash generates strong mechanical ground vibrations, or seismic waves, that propagate thousands of kilometres from the origin.

What makes glacial earthquakes unique is that they do not generate any high-frequency seismic waves. These waves play a vital role in the detection and location of typical seismic sources, such as earthquakes, volcanoes and nuclear explosions.

Due to this difference, glacial earthquakes were only discovered relatively recently, despite other seismic sources having been documented routinely for several decades.

Varying with the seasons

Most glacial earthquakes detected so far have been located near the ends of glaciers in Greenland, the largest ice cap in the Northern Hemisphere.

The Greenland glacial earthquakes are relatively large in magnitude. The largest ones are similar in size to those caused by nuclear tests conducted by North Korea in the past two decades. As such, they have been detected by a high-quality, continuously operating seismic monitoring network worldwide.

The Greenland events vary with the seasons, occurring more often in late summer. They have also become more common in recent decades. The signs may be associated with a faster rate of global warming in the polar regions.

Elusive evidence

Although Antarctica is the largest ice sheet on Earth, direct evidence of glacial earthquakes caused by capsizing icebergs there has been elusive. Most previous attempts to detect Antarctic glacial earthquakes used the worldwide network of seismic detectors.

However, if Antarctic glacial earthquakes are of much lower magnitude than those in Greenland, the global network may not detect them.

In my new study, I used seismic stations in Antarctica itself to look for signs of these quakes. My search turned up more than 360 glacier seismic events, most of which are not yet included in any earthquake catalogue.

The events I detected were in two clusters, near Thwaites and Pine Island glaciers. These glaciers have been the largest sources of sea-level rise from Antarctica.

Earthquakes at the Doomsday Glacier

Thwaites Glacier is sometimes known as the Doomsday Glacier. If it were to collapse completely it would raise global sea levels by 3 meters (10 feet), and it also has the potential to fall apart rapidly.

About two-thirds of the events I detected — 245 out of 362 — were located near the marine end of Thwaites. Most of these events are likely glacial earthquakes due to capsizing icebergs.

The strongest driver of such events does not appear to be the annual oscillation of warm air temperatures that drives the seasonal behavior of Greenland glacier earthquakes.

Instead, the most prolific period of glacial earthquakes at Thwaites, between 2018 and 2020, coincides with a period of accelerated flow of the glacier's ice tongue towards the sea. The ice-tongue speed-up period was independently confirmed by satellite observations.

This speed-up could have been caused by ocean conditions, the effect of which is not yet well understood.

The findings suggest the short-term scale impact of ocean states on the stability of marine-terminating glaciers. This is worth further exploration to assess the potential contribution of the glacier to future sea-level rise.

The second largest cluster of detections occurred near the Pine Island Glacier. However, these were consistently located 60–80 kilometers [37 to 50 miles] from the waterfront, so they are not likely to have been caused by capsizing icebergs.

These events remain puzzling and require follow-up research.

What's next for Antarctic glacial earthquake research

The detection of glacial earthquakes associated with iceberg calving at Thwaites Glacier could help answer several important research questions. These include a fundamental question about the potential instability of the Thwaites Glacier due to the interaction of the ocean, ice and solid ground near where it meets the sea.

Better understanding may hold the key to resolving the current large uncertainty in the projected sea-level rise over the next couple of centuries.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Due to its thick, vast ice sheet, Antarctica appears to be a single, continuous landmass centered over the South Pole and spanning both hemispheres of the globe. The Western Hemisphere sector of the ice sheet is shaped like a hitchhiker’s thumb – an apt metaphor, because the West Antarctic ice sheet is on the go. Affected by Earth’s warming oceans and atmosphere, the ice sheet that sits atop West Antarctica is melting, flowing outward and diminishing in size, all at an astonishing pace.

Much of the discussion about the melting of massive ice sheets during a time of climate change addresses its effects on people. That makes sense: Millions will see their homes damaged or destroyed by rising sea levels and storm surges.

But what will happen to Antarctica itself as the ice sheets melt?

In layers of sediment accumulated on the sea floor over millions of years, researchers like us are finding evidence that when West Antarctica melted, there was a rapid uptick in onshore geological activity in the area. The evidence foretells what’s in store for the future.

A voyage of discovery

As far back as 30 million years ago, an ice sheet covered much of what we now call Antarctica. But during the Pliocene Epoch, which lasted from 5.3 million to 2.6 million years ago, the ice sheet on West Antarctica drastically retreated. Rather than a continuous ice sheet, all that remained were high ice caps and glaciers on or near mountaintops.

About 5 million years ago, conditions around Antarctica began to warm, and West Antarctic ice diminished. About 3 million years ago, all of Earth entered a warm climate phase, similar to what is happening today.

Glaciers are not stationary. These large masses of ice form on land and flow toward the sea, moving over bedrock and scraping off material from the landscape they cover, and carrying that debris along as the ice moves, almost like a conveyor belt. This process speeds up when the climate warms, as does calving into the sea, which forms icebergs. Debris-laden icebergs can then carry that continental rock material out to sea, dropping it to the sea floor as the icebergs melt.

In early 2019, we joined a major scientific trip – International Ocean Discovery Program Expedition 379 – to the Amundsen Sea, south of the Pacific Ocean. Our expedition aimed to recover material from the seabed to learn what had happened in West Antarctica during its melting period all that time ago.

Aboard the drillship JOIDES Resolution, workers lowered a drill nearly 13,000 feet (3,962 meters) to the sea floor and then drilled 2,605 feet (794 meters) into the ocean floor, directly offshore from the most vulnerable part of the West Antarctic ice sheet.

The drill brought up long tubes called “cores,” containing layers of sediments deposited between 6 million years ago and the present. Our research focused on sections of sediment from the time of the Pliocene Epoch, when Antarctica was not entirely ice-covered.

An unexpected finding

While onboard, one of us, Christine Siddoway, was surprised to discover an uncommon sandstone pebble in a disturbed section of the core. Sandstone fragments were rare in the core, so the pebble’s origin was of high interest. Tests showed that the pebble had come from mountains deep in the Antarctic interior, roughly 800 miles (1,300 kilometers) from the drill site.

For this to have happened, icebergs must have calved from glaciers flowing off interior mountains and then floated toward the Pacific Ocean. The pebble provided evidence that a deep-water ocean passage – rather than today’s thick ice sheet – existed across the interior of what is now Antarctica.

After the expedition, once the researchers returned to their home laboratories, this finding was confirmed by analyzing silt, mud, rock fragments, and microfossils that also came up in the sediment cores. The chemical and magnetic properties of the core material revealed a detailed timeline of the ice sheet’s retreats and advances over many years.

One key sign came from analyses led by Keiji Horikawa. He tried to match thin mud layers in the core with bedrock from the continent, to test the idea that icebergs had carried such materials very long distances. Each mud layer was deposited right after a deglaciation episode, when the ice sheet retreated, that created a bed of iceberg-carried pebbly clay. By measuring the amounts of various elements, including strontium, neodymium and lead, he was able to link specific thin layers of mud in the drill cores to chemical signatures in outcrops in the Ellsworth Mountains, 870 miles (1400 km) away.

Horikawa discovered not just one instance of this material but as many as five mud layers deposited between 4.7 million and 3.3 million years ago. That suggests the ice sheet melted and open ocean formed, then the ice sheet regrew, filling the interior, repeatedly, over short spans of thousands to tens of thousands of years.

Creating a fuller picture

Teammate Ruthie Halberstadt combined this chemical evidence and timing in computer models showing how an archipelago of ice-capped, rugged islands emerged as ocean replaced the thick ice sheets that now fill Antarctica’s interior basins.

The biggest changes happened along the coast. The model simulations show a rapid increase in iceberg production and a dramatic retreat of the edge of the ice sheet toward the Ellsworth Mountains. The Amundsen Sea became choked with icebergs produced from all directions. Rocks and pebbles embedded in the glaciers floated out to sea within the icebergs and dropped to the seabed as the icebergs melted.

Long-standing geological evidence from Antarctica and elsewhere around the world shows that as ice melts and flows off the land, the land itself rises because the ice no longer presses it down. That shift can cause earthquakes, especially in West Antarctica, which sits above particularly hot areas of the Earth’s mantle that can rebound at high rates when the ice above them melts.

The release of pressure on the land also increases volcanic activity – as is happening in Iceland in the present day. Evidence of this in Antarctica comes from a volcanic ash layer that Siddoway and Horikawa identified in the cores, formed 3 million years ago.

The long-ago loss of ice and upward motions in West Antarctica also triggered massive rock avalanches and landslides in fractured, damaged rock, forming glacial valley walls and coastal cliffs. Collapses beneath the sea displaced vast amounts of sediment from the marine shelf. No longer held in place by the weight of glacier ice and ocean water, huge masses of rock broke away and surged into the water, producing tsunamis that unleashed more coastal destruction.

The rapid onset of all these changes made deglaciated West Antarctica a showpiece for what has been called “catastrophic geology.”

The rapid upswell of activity resembles what has happened elsewhere on the planet in the past. For instance, at the end of the last Northern Hemisphere ice age, 15,000 to 18,000 years ago, the region between Utah and British Columbia was subjected to floods from bursting glacial meltwater lakes, land rebound, rock avalanches and increased volcanic activity. In coastal Canada and Alaska, such events continue to occur today.

Dynamic ice sheet retreat

Our team’s analysis of rocks’ chemical makeup makes clear that West Antarctica doesn’t necessarily undergo one gradual, massive shift from ice-covered to ice-free, but rather swings back and forth between vastly different states. Each time the ice sheet disappeared in the past, it led to geological mayhem.

The future implication for West Antarctica is that when its ice sheet next collapses, the catastrophic events will return. This will happen repeatedly, as the ice sheet retreats and advances, opening and closing the connections between different areas of the world’s oceans.

This dynamic future may bring about equally swift responses in the biosphere, such as algal blooms around icebergs in the ocean, leading to an influx of marine species into newly opened seaways. Vast tracts of land upon West Antarctic islands would then open up to growth of mossy ground cover and coastal vegetation that would turn Antarctica more green than its current icy white.

Our data about the Amundsen Sea’s past and the resulting forecast indicate that onshore changes in West Antarctica will not be slow, gradual or imperceptible from a human perspective. Rather, what happened in the past is likely to recur: geologically rapid shifts that are felt locally as apocalyptic events such as earthquakes, eruptions, landslides and tsunamis – with worldwide effects.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Scientists have pulled a 6 million-year-old chunk of ice out of Antarctica — the oldest directly dated ice ever found — and it's helping them to reconstruct Earth's ancient climate.

The record-breaking ice, along with air bubbles trapped inside, is more than double the age of the previously oldest-known ice samples, which are around 2.7 million years old, according to a new study published Oct. 28 in the journal PNAS.

"Ice cores are like time machines that let scientists take a look at what our planet was like in the past," study lead author Sarah Shackleton, an assistant scientist at the Woods Hole Oceanographic Institution in Massachusetts, said in a statement. "The Allan Hills cores help us travel much further back than we imagined possible."

The ice and air dates to the Miocene age (23 million to 5.3 million years ago), when Earth was much warmer, sea levels were higher and the planet was filled with now-extinct creatures, including saber-toothed cats, okapi-like giraffes, Arctic rhinos and the first mammoths.

Shackleton and her colleagues discovered the record-breaking ice in the remote Allan Hills blue ice area of East Antarctica between 2019 and 2023. The Allan Hills ice field is around 6,500 feet (2,000 meters) above sea level, according to the study.

To obtain samples, the researchers drilled 330 to 660 feet (100 to 200 meters) down into an ice sheet. They then dated the excavated ice cores by measuring radioactive decay in argon isotopes present in the air pockets. Tracing oxygen isotopes in the cores also enabled the scientists to determine that the Allan Hills region has undergone a steady cooling of about 22 degrees Fahrenheit (12 degrees Celsius) over the past 6 million years, according to the statement — released by Oregon State University, which was also involved in the research.

While Antarctica — and Earth as a whole — has steadily cooled over recent millennia, humans are now rapidly increasing global temperatures by releasing copious amounts of heat-trapping greenhouse gases into the atmosphere. The authors of the new study said that by investigating the ice cores, they could decipher ancient levels of greenhouse gases and ocean warming, and thus better understand natural drivers of climate change across Earth’s history.

The Allan Hills region preserved the ice thanks to a variety of factors, both known and unknown, including near-static surface ice movement and rugged mountain features that locked the ice in place.

"We're still working out the exact conditions that allow such ancient ice to survive so close to the surface," Shackleton said. "Along with the topography, it's likely a mix of strong winds and bitter cold. The wind blows away fresh snow, and the cold slows the ice to almost a standstill. That makes Allan Hills one of the best places in the world to find shallow old ice, and one of the toughest places to spend a field season."

A potent greenhouse gas has begun seeping out of the Antarctic seafloor in dozens of places, scientists have discovered.

Researchers documented the emergence of these methane seeps in shallow regions of the Ross Sea, a bay off the southern coast of Antarctica. The patches of leaking gas could be caused by global warming, and they could also threaten to accelerate it further, according to a new study published Oct. 1 in the journal Nature Communications.

"Every time we discover or hear of a new one, we feel immediate excitement, but that excitement is quickly replaced with anxiety and concern about what it all means," study lead author Sarah Seabrook, a marine scientist at the research institute Earth Sciences New Zealand, said in a statement.

"If they follow the behaviour of other global seep systems, there is the potential for rapid transfer of methane to the atmosphere from a source that is not currently factored into future climate change scenarios," Seabrook added.

Methane (CH₄) is a greenhouse gas that traps heat in the atmosphere by absorbing outgoing radiation. When methane first enters the atmosphere, it is a lot more effective at trapping heat than carbon dioxide (CO₂), being about 80 times more potent across the first 20 years it's in the atmosphere. This makes methane a particularly aggressive short-term driver of climate change. (CO₂ stays in the atmosphere for longer, so it's a more significant long-term driver.)

About 60% of methane emissions come from human activities such as farming and burning fossil fuels, while the remaining 40% come from natural sources. Scientists are concerned that as the planet gets warmer, more natural methane and carbon dioxide sources, such as those in melting permafrost, are being unlocked, creating a positive feedback loop that accelerates warming even further.

Researchers have previously spotted tens of thousands of methane leaks in the Arctic, but prior to the new study, there was only one confirmed Antarctic methane seep, identified in 2011. Underwater seeps create streams of bubbles as methane and other chemicals dissolve in ocean water following their release from beneath the seabed. White mats of microbial communities live around seeps, making them identifiable on the seafloor.

In the new study, researchers used acoustic surveys, divers and a remotely operated vehicle to explore seeps located between 16 feet (5 meters) and 787 feet (240 m) below the icy surface of the Ross Sea, off the Antarctic mainland. The team initially only went to investigate one seep in Cape Evans, located on the west side of Ross Island, and were surprised to find the seafloor littered with them.

"Last year, we went to Cape Evans to look at one small area where gas bubbles had been discovered and were hoping to find that one site still bubbling," Seabrook said. "Instead, we found dozens more."

The researchers studied areas that have been regularly surveyed for decades, meaning that the seeps must be a new feature. It's not known exactly what is causing the seeps to appear, but the researchers noted that similar processes in the Arctic and paleorecord (past environments) have been attributed to climate-driven cryospheric change — the degradation of Earth's ice that previously locked these chemicals in place.

It's unclear how much methane might be leaving Antarctica and reaching our atmosphere, nor how much remains trapped beneath its thawing ice, but the researchers are concerned that the seeps could be widespread. This raises fears of positive feedback loops as well as a variety of other knock-on effects caused by methane, such as ocean acidification.

Seabrook and her colleagues recommended coordinated, international efforts to urgently study the seeps.

"If these seeps keep emerging at the areas we are working in, it really begs the question of what the shallow coastal environment of Antarctica may look like five or 10 years from now," Seabrook said. "This system is rapidly changing before our eyes from one year to the next."

The infamous ship Endurance, which sank in Antarctica in 1915, wasn't as well built for a polar voyage as previously thought — and its owner was likely aware of its shortcomings.

Explorer Ernest Shackleton sailed Endurance to Antarctica in 1914 as part of a failed British expedition to cross the continent on foot. The ship became trapped in the ice in the Weddell Sea, where it remained for 10 months before it sank, supposedly when its rudder was torn off by the ice. But there's more to the story, according to a new study.

"Endurance clearly had several structural deficiencies compared with other early Antarctic ships," study author Jukka Tuhkuri, a professor of solid mechanics at Aalto University in Finland, said in a statement. "Not only does this challenge the romantic narrative that it was the strongest polar ship of its time, but it also belies the simplistic idea that the rudder was the ship's Achilles' heel."

After joining Endurance22, the expedition that located the sunken wreck of Endurance in March 2022, Tuhkuri analyzed the ship's structure and studied how it may have responded to the moving ice that would have compressed and strained the ship's hull. He also reviewed the journals of several of Endurance's crewmembers, along with some of Shackleton's letters to his wife and to fellow sailors.

In the new study, published Monday (Oct. 6) in the journal Polar Record, Tuhkuri outlined some structural issues that might have played a role in Endurance's demise. The ship had a relatively large engine room, which was difficult to reinforce and, therefore, weakened a large section of the hull. And unlike many other polar ships of the time, Endurance didn't have diagonal beams installed to support and strengthen its hull.

The crew's journals also suggested that the loss of the ship's rudder wasn't what caused it to sink. It may have played a role, but the ship also suffered serious damage to its sternpost, keel, hull and deck beams while trapped in the ice.

"Even simple structural analysis shows that the ship was not designed for the compressive pack ice conditions that eventually sank it," Tuhkuri said. "The danger of moving ice and compressive loads — and how to design a ship for such conditions — was well understood before the ship sailed south. So we really have to wonder why Shackleton chose a vessel that was not strengthened for compressive ice."

Based on records from before the expedition, as outlined in the study, it's likely Shackleton's decision wasn't made in ignorance. A letter Shackleton sent to his wife in 1914 lamented that Endurance wasn't as strong as other ships he had sailed on for prior expeditions. And in 1911, he had recommended adding diagonal supports to a polar ship called Deutschland, which went on to survive the same icy conditions that disabled Endurance. It's unclear why those same diagonal supports weren't added to Endurance before it set sail.

For now, the reasons behind Shackleton's decision to sail Endurance into the Antarctic ice pack remain a mystery.

"We can speculate about financial pressures or time constraints, but the truth is we may never know why Shackleton made the choices that he made," Tuhkuri said. "At least now we have more concrete findings to flesh out the stories."

Three million years ago, an extinct relative of todays's great penguins — emperors and kings — lived in Aotearoa New Zealand.

We know this because our new study describes a spectacular fossilized skull of a great penguin found on the Taranaki coast.

Overall, it is 31% longer than the skull of an emperor penguin (Aptenodytes forsteri), which can be more than a meter tall and weigh upwards of 35 kilograms.

Compared to emperor penguins, however, the Taranaki great penguin had a much stronger and longer beak. It probably looked more like a king penguin (Aptenodytes patagonicus), only much bigger.

At the time, the world was warmer than today. But when the climate cooled, this penguin vanished.

We argue the cold wasn't to blame because crested and little penguins in New Zealand weathered the same change and remained. Great penguins shifted south and today live in the frozen wastes of Antarctica. So what drove their ancient relative to extinction?

The sediments that now form beach-side cliffs in South Taranaki were deposited at a time when global temperatures were about 3°C above those of the pre-industrial era. Fossils from this period are transforming our understanding of how biodiversity might respond to rising temperatures.

For example, Aotearoa was home to box fish and monk seals, both of which are still (sub)tropical species today. In a strange contradiction, they coexisted with great penguins — now only found in much colder climates — in ancient New Zealand.

The northernmost breeding colonies of king penguins today are around latitude 46.1°S in the subantarctic Crozet Islands, where seawater temperatures reach 3-10°C. From there, it only gets colder towards the higher latitudes where emperor penguins live.

Three million years ago, Aotearoa's great penguins extended as far north as 40.5°S, where South Taranaki was located then. They foraged in waters that were 20°C, much warmer than their relatives experience today.

This balmy existence ended with the Pleistocene ice ages around 2.58 million years ago. Ice extent and sea level shifted back and forward as temperatures fluctuated and ultimately ratcheted downwards. But why would such cooling eradicate giant penguins, which thrive under polar conditions today, from New Zealand?

Giant aerial predators

Fossil evidence for giant penguins in Aotearoa is limited and the exact reasons for their demise remain unclear. Even so, their sheer presence suggests they were less constrained by sea surface temperatures than previously thought. Another mechanism must be at play.

Up until about 500 years ago, Aotearoa was the hunting ground of the giant Haast's eagle and the huge Forbes' harrier. These were big raptors. They included large birds like moa in their diet. Their ancestors arrived from Australia inside the last three million years.

Based on what we see with living great penguins, the Taranaki great penguin almost certainly formed large exposed colonies along the coast. These could have been easy targets for a giant eagle or harrier hunting from the air.

By contrast, the smaller penguins still found in Aotearoa today have more cryptic breeding behavior. They nest in burrows, natural crevices and dense vegetation, and tend to cross beaches at night, which may have helped them avoid aerial predators.

Predation on land is just one hypothesis, though, to help explain why these penguins became extinct in the region while others survived. Other possibilities include changes in the marine environment.

We know that reduced food availability can be devastating for penguins, but it is challenging to see why this would single out the great penguins.

Importantly, our study provides new insight into the habitat tolerances of great penguins. Both king and emperor penguins today can withstand temperatures up to 20°C higher than those they usually forage in.

Three million years ago, their relative experienced such warmth. As the world continues to warm, we need to remember that the geographic range of a species can change as circumstances change.

The marine ecosystem of Aotearoa will move into the habitable zone of many new species, making investigations of the last warm period more important than ever before.

We would like to acknowledge our research co-author Dan Ksepka from The Bruce Museum, Kerr Sharpe-Young for discovering the fossil, and Ngāti Ruanui and Ngāruahine for supporting the collection and research of fossils from their rohe.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Scientists have identified 85 previously unknown lakes hidden beneath Antarctica's ice using a decade's worth of satellite data.

The newfound lakes are "active," meaning they periodically drain and refill, changing size and shape over months and years, the researchers said. This subglacial activity affects the stability of glaciers and their grinding movement over the Antarctic bedrock, which in turn could impact global sea levels, the team noted.

"It was fascinating to discover that the subglacial lake areas can change during different filling or draining cycles," study co-author Anna Hogg, a professor of Earth observation at the University of Leeds in the U.K., said in a statement from the European Space Agency (ESA). "This shows that Antarctic subglacial hydrology is much more dynamic than previously thought, so we must continue to monitor these lakes as they evolve in the future."

Before this latest discovery, 146 active subglacial lakes were already known in Antarctica. The new study brings the total number of active lakes to 231 and adds to scientists' understanding of when and how subglacial lakes drain and refill, study lead author Sally Wilson said in the statement.

"It is incredibly difficult to observe subglacial lake filling and draining events," said Wilson, who is a doctoral student in the Institute for Climate and Atmospheric Science at the University of Leeds. "Only 36 complete cycles, from the start of subglacial filling through to the end of draining, had been observed worldwide before our study. We observed 12 more complete fill-drain events, bringing the total to 48."

Subglacial lakes are pools of meltwater that form when geothermal heat from Earth's interior rises to the base of an ice sheet, or when enough frictional heat is generated by ice grinding on the bedrock. Subglacial lakes can sometimes periodically drain, creating a flow of water that lubricates the bottom of the ice sheet and helps it slide on the bedrock, accelerating the movement of ice toward the ocean.

For the study, the researchers analyzed data captured between 2010 and 2020 from ESA's Cryosat-2 satellite, which measures variations in the thickness of sea ice, glaciers and ice sheets worldwide. Cryosat-2 carries an instrument called a radar altimeter that can detect small changes in the height of ice features, including changes resulting from lakes draining and filling at the base of the ice.

The data revealed dozens of locations where the Antarctic Ice Sheet is sinking and rising slightly as a result of meltwater draining and refilling subglacial lakes beneath the surface. The observations also showed 25 clusters of lakes and five never-before-seen subglacial lake networks with interconnected drain-and-refill cycles, the researchers wrote in the study, which was published Sept. 19 in the journal Nature Communications.

The results are important because they improve scientists' understanding of ice sheet dynamics and how these impact global sea levels, which could help researchers design more accurate climate and Earth models. "The numerical models we currently use to project the contribution of entire ice sheets to sea level rise do not include subglacial hydrology," Wilson said. "These new datasets of subglacial lake locations, extents, and timeseries of change, will be used to develop our understanding of the processes driving water flow beneath Antarctica."

Some subglacial lakes in Antarctica are stable, meaning they do not drain and refill. An example is Lake Vostok, which sits beneath the East Antarctic Ice Sheet and holds more than enough water to fill the Grand Canyon, according to the statement. If Lake Vostok ever started emptying, it could affect the entire ice sheet and cause global sea levels to rise, the researchers noted.

"The more we understand about the complex processes affecting the Antarctic Ice Sheet, including the flow of meltwater at the base of the ice sheet, the more accurately we will be able to project the extent of future sea level rise," Martin Wearing, a digital twin Earth scientist and ESA's Polar Science Cluster coordinator, concluded in the statement.

Antarctica quiz: Test your knowledge on Earth's frozen continent

Our planet continues to warm because of greenhouse gas emissions from human activities. The polar regions are especially vulnerable to this warming. Sea ice extent is already declining in both the Arctic and Antarctic. The Greenland and Antarctic ice sheets are melting, and abrupt changes in both polar environments are underway.

These changes have significant implications for society through sea level rise, changes to ocean circulation and climate extremes. They also have substantial consequences for polar ecosystems, including polar bears and emperor penguins, which have become iconic symbols of the impacts of climate change.

The most effective way to mitigate these changes, and lower the risk of widespread impacts, is reducing greenhouse gas emissions. Yet decarbonization is slow, and current projections suggest temperature increases of roughly 3°C by 2100.

Given the expected change, and the importance of the polar regions for planetary health, some scientists and engineers have proposed technological approaches, known as geoengineering, to soften the blow to the Arctic and Antarctic.

In research published today in Frontiers in Science, my colleagues and I assessed five of the most developed geoengineering concepts being considered for the polar regions. We found none of them should be used in the coming decades. They are extremely unlikely to mitigate the effects of global warming in polar regions, and are likely to have serious adverse and unintended consequences.

What is polar geoengineering?

Geoengineering encompasses a wide range of ideas for deliberate large-scale attempts to modify Earth's climate. The two broadest classes involve removing carbon dioxide from the atmosphere and increasing the amount of sunlight reflected back into space (known as "solar radiation modification").

For the polar regions, here are the five most developed concepts.

Stratospheric aerosol injection is a solar radiation modification approach that involves introducing finer particles (such as sulphur dioxide or titanium dioxide) into the stratosphere to reflect sunlight back out to space. In this case, the focus is specifically on the polar regions.

Sea curtains are flexible, buoyant structures anchored to the seafloor at 700 metres to 1,000m depth and rising 150m to 500m. The aim is to prevent warm ocean water from reaching and melting ice shelves (floating extensions of ice that slow the movement of ice from Greenland and Antarctica into the ocean) and the grounding lines of ice sheets (where the land, ice sheet and ocean meet).

Sea ice management includes two concepts. The first is the scattering of glass microbeads over fresh Arctic sea ice to make it more reflective and help it survive longer. The second is pumping seawater onto the sea ice surface, where it will freeze, with the aim of thickening the ice — or into the air to produce snow, to the same general effect, using wind-powered pumps.

Basal water removal targets the ice streams found in the Antarctic and Greenland ice sheets. These streams are fast-moving rivers of ice that flow toward the coast, where they can enter the ocean and raise sea levels. Water at their base acts as a lubricant. This concept proposes to remove water from their base to increase friction and slow the flow. The concept is thought to be especially relevant to Antarctica, which has much less surface melting than Greenland, and therefore melt is more about the base of the ice sheet than its surface.

Ocean fertilization involves adding nutrients such as iron to polar oceans to promote the growth of phytoplankton. These tiny creatures absorb carbon dioxide from the atmosphere, which gets stored in the deep ocean when they die and sink.

The risk of false hopes

In our research, we assessed each of these concepts against six criteria. These included: scope of implementation; feasibility; financial costs; effectiveness; environmental risks; and governance challenges.

This framework offers an objective way of assessing all such concepts for their merits.

None of the proposed polar geoengineering concepts passed scrutiny as concepts that are workable over the coming decades. The criteria we used show each of the concepts faces multiple difficulties.

For example, to cover 10% of the Arctic Ocean with pumps to deliver seawater to freeze within ten years, one million pumps per year would need to be deployed. The estimated costs of sea curtains (US$1 billion per kilometre) are underestimates of similar-scale projects in easier environments, such as the Thames Barrier near London, by six to 25 times.

One project that planned to spread glass microbeads on ice has also been shut down citing environmental risks. And at their most recent meeting, the majority of Antarctic Treaty Consultative Parties made clear their view that geoengineering should not be conducted in the region.

Polar geoengineering proposals raise false hopes for averting some disastrous consequences of climate change without rapidly cutting greenhouse gas emissions.

They risk encouraging complacency about the urgency of achieving net zero emissions by 2050 or may be used by powerful actors as an excuse to justify continued emissions.

The climate crisis is a crisis. Over the time available, efforts are best focused on decarbonization. The benefits are rapidly realizable within the near term.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

An iceberg that was once the size of Rhode Island and the biggest in the world has lost about 80% of its mass since May, scientists at the British Antarctic Survey (BAS) report.

Known as A23a, the "megaberg" has been rapidly disintegrating since becoming trapped in a current flowing counterclockwise around South Georgia Island in the South Atlantic Ocean, Andrew Meijers, a polar oceanographer with the BAS, told CNN.

A23a was swept up by the current in May after spending several months grounded on the continental shelf just off South Georgia Island. "It has been following the strong current jet known as the Southern Antarctic Circumpolar Current Front (SACCF)," Meijers said, adding that the iceberg will likely end up traveling away from the island in a northeast direction before breaking up completely.

Dubbed the "queen of icebergs," A23a broke off Antarctica's Filchner-Ronne ice shelf (which borders the Weddell Sea) in 1986. The giant berg immediately ran aground, remaining stuck to the seabed in the Weddell Sea for more than 30 years. It was crowned the biggest iceberg in the world and has only briefly been surpassed by others over the years, including iceberg A68 between 2017 and 2020 and iceberg A76 in 2021.

A23a finally made a move in 2020, probably because the ice that anchored it to the seabed melted away. But the iceberg quickly became trapped again, this time in a spinning vortex called a Taylor column, caused by an underwater mountain. It managed to free itself in December 2024 and was reported in January to be barreling toward South Georgia Island.

In January, A23a weighed almost 1.1 trillion tons (1 trillion metric tons) and measured 1,418 square miles (3,672 square kilometers), CNN reported. Now, the megaberg is not so mega anymore, measuring 656 square miles (1,700 square km), or about one-fifth of its size just eight months ago.

Related: 'We didn't expect to find such a beautiful, thriving ecosystem': Hidden world of life discovered beneath Antarctic iceberg

"The iceberg is rapidly breaking up, and shedding very large chunks, themselves designated large icebergs by the US national ice center that tracks these," Meijers said.

A68 and A76 also began disintegrating when they drifted close to South Georgia, suggesting the SACCF is to blame for breaking up the icebergs — although A23a remained intact for longer than either A68 or A76 did in the current's wake, Meijers said.

A23a has relinquished its title of the biggest iceberg in the world to iceberg D15a, which is currently located near Australia's Davis research station in Antarctica. D15a measures around 1,160 square miles (3,000 square km) and appears to be staying in place, Meijers said.

For now, A23a is the second-largest iceberg in the world, but it will quickly drop down the ranks as it continues to fall apart over the coming weeks, he said. Eventually, fragments of A23a will become so small that scientists will stop monitoring them, with the onset of southern spring likely to contribute to their melting into mini bergs, Meijers added.

Large icebergs could end up in the waters off South Georgia Island more frequently in the future due to climate change, a BAS spokesperson told CNN. There isn't enough data at the moment to say whether more megabergs are forming or will form as a result of global warming, but the number of icebergs calving from Antarctica is increasing, Meijers said.

Antarctica is extremely vulnerable to warming and scientists are already seeing dramatic changes in the frozen continent's natural cycles.

Update, Oct. 21, 2025 at 1:17 pm ET: Live Science has learned that Iceland is no longer mosquito-free. Three mosquitoes — two females and one male — were found in the garden of a private residence between Oct. 16 and Oct. 18 in the municipality of Kjósarhreppur (also known as Kjós), according to the Iceland Monitor. In a Facebook post in the group Skordýr á Íslandi ("Insects in Iceland"), the man who found them, Björn Hjaltason, said "I could tell right away that this was something I had never seen before."

Matthías Alfreðsson, an entomologist at the Icelandic Institute of Natural History, confirmed that the mosquitoes belong to the species Culiseta annulata, the Iceland Monitor reported.

"The last fortress has fallen," Hjaltason wrote in the Facebook post, although it still remains to be seen if the mosquitoes will survive Iceland's winter.

The original article, posted Sept. 1, is below.

Mosquitoes bite people in almost every country across the globe. But are there any countries that don't have this blood-sucking pest?

The answer is "yes," there is one country without mosquitoes: Iceland. While its neighbors — including Norway, Scotland and Greenland — are home to multiple mosquito species, Iceland remains mosquito-free. (Of note, Antarctica is also mosquito-free, but the southern continent is not a country.)

So how is it possible for Iceland to have no mosquitoes?

Scientists have several theories. One idea is that mosquitoes simply haven't made it to Iceland yet. The island nation is separated from its neighbors by hundreds of miles of ocean, creating a natural barrier that makes it difficult for mosquitoes to arrive by flight.

Yet mosquitoes do get transported aboard planes. Gísli Már Gíslason, a professor emeritus of limnology (the study of lakes and fresh water) at the University of Iceland, confirmed this after capturing a mosquito on a flight from Greenland to Iceland. Furthermore, mosquitoes can survive for hours on aircraft landing gear, even in freezing temperatures, he said in an interview with Reykavík Grapevine, an English-language publication in Iceland, in 2017.

So if mosquitoes have arrived, why haven't they established populations?

Gíslason explained that a lack of suitable breeding habitats is unlikely. Iceland has plenty of ponds and marshes near its airports — ideal places for mosquitoes to lay eggs. Instead, the most probable explanation is Iceland's harsh climate.

A mosquito's life cycle consists of four stages: egg, larva, pupa (like a caterpillar chrysalis) and adult. Adult mosquitoes lay their eggs in water. These eggs hatch into larvae, which develop in pupae. An adult mosquito then emerges from the pupa.

Robert Jones, an insect biologist and assistant professor at the London School of Hygiene & Tropical Medicine, told Live Science that mosquito larvae require unfrozen liquid water to develop. In extremely cold regions like the Canadian Arctic, some mosquito species survive by entering dormancy in the egg stage, where they can endure months of frozen water.

"In warmer areas, such as parts of Central Europe, mosquitoes may survive the winter as eggs or larvae in relatively sheltered bodies of water that do not freeze, or as adults hidden in burrows and other protected sites," he said.

Iceland's climate falls in between: Long winters and frequent freeze-thaw cycles in autumn and spring cause water bodies to freeze, melt and refreeze repeatedly. "These cycles disrupt development and kill mosquito eggs and larvae before they can emerge as adults, making it much harder for populations to establish," Jones said.

Although Iceland's geothermal pools remain unfrozen in winter, their temperatures may be too warm for larvae of any mosquito species adapted to high latitudes. "In addition, the chemical composition of geothermal waters is unlikely to be suitable for mosquito development," he said.

However, with climate change, Iceland's mosquito-free status might not last forever. Jones noted that warmer springs and autumns could create longer periods of unfrozen standing water, allowing mosquitoes to establish permanent populations.

Immo Hansen, a professor of biology at New Mexico State University, agrees. "We're currently seeing tropical mosquitoes expanding their range north in the United States," he told Live Science, largely because that region's winters are warming.

If mosquitoes do eventually spread to Iceland, it wouldn't be the first time a mosquito-free zone disappeared. Hawaii, the most isolated archipelago in the world, was mosquito-free until 1826, when European and American ships inadvertently introduced them. Thanks to Hawaii's favorable climate, mosquitoes thrived and spread rapidly across the islands. Since then, climate change has pushed mosquitoes into Hawaii's higher-elevation forests that were once too cool for them to survive.

Despite the potential for mosquitoes to arrive in Iceland, the risk of disease-carrying species — like those in the Aedes genus, which are known to transmit diseases such as dengue and chikungunya — establishing there remains low because these insects need tropical and subtropical climates to survive, Jones said. While Southern Europe faces increased risks of such outbreaks due to climate change and modern transport, "modeling studies suggest that Northern Europe will remain largely unsuitable for dengue transmission even by 2080," he said.

Antarctica has long been seen as a remote, unchanging environment. Not any more.

The ice-covered continent and the surrounding Southern Ocean are undergoing abrupt and alarming changes. Sea ice is shrinking rapidly, the floating glaciers known as ice shelves are melting faster, the ice sheets carpeting the continent are approaching tipping points and vital ocean currents show signs of slowing down.

Published today in Nature, our new research shows these abrupt changes are already underway — and likely to significantly intensify in the future.

Several authors of this article have witnessed these startling changes during fieldwork on the ice. These changes spell bad news for wildlife, both iconic and lesser known. But the changes will reach much further. What's happening in Antarctica right now will affect the world for generations to come, from rising sea levels to extreme changes in the climate system.

What is an abrupt change?

Scientists define an abrupt change as a climatic or environmental shift taking place much faster than expected.

What makes abrupt changes so concerning is they can amplify themselves. For example, melting sea ice allows oceans to warm more rapidly, which melts more sea ice. Once triggered, they can be difficult or even impossible to reverse on timescales meaningful to humans.

Related: Scientists discover long-lost giant rivers that flowed across Antarctica up to 80 million years ago

While it's common to assume incremental warming will translate to gradual change, we're seeing something very different in Antarctica. Over past decades, the Antarctic environment had a much more muted response overall to human-caused climate warming compared to the Arctic. But about a decade ago, abrupt changes began to occur.

Shrinking sea ice brings cascading change

Antarctica's natural systems are tightly interwoven. When one system is thrown out of balance, it can trigger cascading effects in others.

Sea ice around Antarctica has been declining dramatically since 2014. The expanse of sea ice is now shrinking at double the rate of Arctic sea ice. We found these unfolding changes are unprecedented — far outside the natural variability of past centuries.

The implications are far reaching. Sea ice has a reflective, high-albedo surface which reflects heat back to space. When there's less sea ice, more heat is absorbed by darker oceans. Emperor penguins and other species reliant on sea ice for habitat and breeding face real threats. Less sea ice also means Antarctica's ice shelves are more exposed to waves.

Vital ocean currents are slowing

The melting of ice is actually slowing down the deep ocean circulation around Antarctica. This system of deep currents, known as the Antarctic Overturning Circulation, plays a critical role in regulating Earth's climate by absorbing carbon dioxide and distributing heat.

In the northern hemisphere, the Atlantic Meridional Overturning Circulation is facing a slowdown.

We're now observing a similar risk in Southern Ocean currents. Changes to the Antarctic Overturning Circulation may unfold at twice the rate of the more famous North Atlantic counterpart.

A slowdown could reduce how much oxygen and carbon dioxide the ocean absorbs and leave vital nutrients at the seafloor. Less oxygen and fewer nutrients would have major consequences for marine ecosystems and climate regulation.

Melting giants

The West Antarctic Ice Sheet as well as some regions of East Antarctica are now losing ice and contributing to sea level rise. Ice loss has increased sixfold since the 1990s.

The West Antarctic Ice Sheet alone has enough ice to raise global sea levels by more than five metres — and scientists warn we could be nearing the point where this ice sheet could collapse even without substantial further warming, though this might take centuries to millennia.

These enormous ice sheets represent the risk of a global tipping point. They contribute the greatest uncertainty to projections of future sea level rise because we don't know just how quickly they could collapse.

Worldwide, at least 750 million people live in low-lying areas near the sea. Rising sea levels threaten coastal infrastructure and communities globally.

Wildlife and ecosystems under threat

Antarctica's biological systems are also undergoing sudden shifts. Ecosystems both under the sea and on land are being reshaped by warming temperatures, unreliable ice conditions and human activity bringing pollution and the arrival of invasive species.

It's essential to protect these ecosystems through the Antarctic Treaty, including creating protected areas of land and sea and restricting some human activities. But these conservation measures won't be enough to ensure emperor penguins and leopard seals survive. That will require decisive global action to reduce greenhouse gas emissions.

Which future?

Antarctica is often seen as a symbol of isolation and permanence. But the continent is now changing with disturbing speed — much faster than scientists anticipated.

These abrupt changes stem largely from the extra heat trapped by decades of unchecked greenhouse gas emissions. The only way to avoid further abrupt changes is to slash emissions rapidly enough to hold warming as close to 1.5°C as possible.

Even if we achieve this, much change has already been set in motion. Governments, businesses and coastal communities must prepare for a future of abrupt change. What happens in Antarctica won't stay there.

The stakes could not be higher. The choices made now will determine whether we face a future of worsening impacts and irreversible change or one of managed resilience to the changes already locked in.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Scientists have discovered a long-lost landscape that's been preserved beneath the Antarctic Ice Sheet for 30 million years.

Erosion by ancient rivers appears to have carved large, flat surfaces beneath the ice in East Antarctica between 80 million and 34 million years ago. Understanding how these features formed, and how they continue to affect the landscape, could help refine predictions of future ice loss, researchers reported July 11 in the journal Nature Geoscience.

"We've long been intrigued and puzzled about fragments of evidence for 'flat' landscapes beneath the Antarctic ice sheets," study co-author Neil Ross, a geophysicist at Newcastle University in the U.K., said in a statement. "This study brings the jigsaw pieces of data together, to reveal the big picture: how these ancient surfaces formed, their role in determining the present-day flow of the ice, and their possible influence on how the East Antarctic Ice Sheet will evolve in a warming world."

If the East Antarctic Ice Sheet were to melt entirely, it could raise global sea levels by more than 160 feet (50 meters). But accurately predicting how much the ice sheet might melt in the coming years requires scientists to know its past behavior and the conditions at its base.

In the new study, the researchers used radar data from four previous surveys to map the shape of the bedrock beneath the ice.

"When we were examining the radar images of the sub-ice topography in this region, these remarkably flat surfaces started to pop out almost everywhere we looked," study co-author Guy Paxman, a polar geophysicist at Durham University in the U.K., said in the statement. "The flat surfaces we have found have managed to survive relatively intact for over 30 million years, indicating that parts of the ice sheet have preserved rather than eroded the landscape."

The flat expanses, which were interspersed with deep troughs, covered a 2,175-mile (3,500 kilometers) section of the East Antarctic coastline. They likely formed before the East Antarctic Ice Sheet existed but after the supercontinent Gondwana (which contained modern-day Antarctica, Australia, Africa, and India) broke apart.

This helped the researchers to date the flat sections to between 80 million and 34 million years ago.

Atop these flat surfaces, the Antarctic ice moves fairly slowly. But in the troughs between them, the ice flows much faster. Meltwater may have carved these troughs by flowing through natural dips as the East Antarctic Ice Sheet expanded millions of years ago.

The slow flow of ice above the flat surfaces could be regulating ice loss from the continent, the researchers wrote in the study. Further research, such as obtaining and analyzing rock samples from under the ice, could refine projections of future ice loss and sea level rise.

"Information such as the shape and geology of the newly mapped surfaces will help improve our understanding of how ice flows at the edge of East Antarctica," Paxman said. "This in turn will help make it easier to predict how the East Antarctic Ice Sheet could affect sea levels under different levels of climate warming in the future."

Antarctica's waters are getting saltier and driving a collapse in its sea ice — and scientists aren't sure why.

Antarctic sea ice has been declining since 2015, defying model predictions to hit a record 0.6 million square miles (1.55 million square kilometres) below its expected average extent in 2023. At winter's peak in July of that year, the region was missing a chunk of ice bigger than Western Europe, and it's showing no signs of recovery.

This decline — the largest environmental shift seen anywhere on Earth in recent decades — will have ripple effects on the world's climate.

Now, scientists have linked the decline to an unexpected and yet-to-be-explained rise in the saltiness of the waters surrounding the continent. The researchers published their findings June 30 in the journal PNAS.

"We were surprised. It's a counterintuitive result because we usually associate melting ice with freshening of the ocean," study lead-author Alessandro Silvano, a senior scientist at the University of Southampton, told Live Science. "This points to a more profound structural shift in the Southern Ocean — not just sea ice, but also the ocean beneath."

Troubled waters

The sea ice surrounding Earth's poles melts in the summer and freezes in the winter, fluctuating between minimums and maximums. In Antarctica, this ice acts as a moat that protects the continent's increasingly precarious land ice from warming ocean waters, while also reflecting some of the sun's energy back into space and trapping carbon dioxide underneath the ocean's surface.

Related: 'We were in disbelief': Antarctica is behaving in a way we've never seen before. Can it recover?

Since satellites began monitoring sea ice extent in 1979, Arctic ice coverage has plunged by more than 12% each decade. Yet the Antarctic's ice continued to steadily grow, hitting an all-time high in 2014. But this trend reversed into a precipitous, worsening fall in 2016, marking a fundamental shift.

Scientists agree that the underlying driver of this switch is climate change. Yet sea ice forms at the boundary between the ocean and the air, which are both surprisingly complex systems. This, alongside the Southern Ocean’s remoteness, makes predicting how intricate warming mechanisms will play out upon the ice difficult.

To investigate, the researchers behind the new study turned to the European Space Agency's Soil Moisture and Ocean Salinity satellite, which measures the subtle changes extra salinity makes to the brightness of microwaves bouncing off the ocean's surface. This signal is messy, requiring cutting-edge algorithms to untangle, meaning that analyzing it only recently became possible.

After examining daily readings from 2011 to 2023, the researchers found that the sea ice's decline and reopening of giant holes in its cover (such as the Weddell Sea's Maud Rise polynya) coincided with a sharp increase in salinity. They were shocked by their result, doubting it until it was confirmed by data from floating buoys.

Conventional wisdom suggests that as temperatures increase, melting ice spilling from Antarctic ice shelves should increase the ocean surface's freshwater content. Instead, some unknown process is making the water more salty.

"The precise drivers remain unclear," Silvano said. "One possibility is that salt stored in deeper layers of the ocean were brought up to the surface — a process potentially triggered by changes in ocean circulation or atmospheric forcing. We're actively investigating how and why this structural change began."

The increasing salt content will likely bring greater warming to the surface waters and ever faster melting of the ice. Salt water is denser than fresh water, so a freshwater layer at the top of the water column acts as a lid, preventing the warmer water that usually circulates in deeper layers from reaching the surface.

Sea ice is also responsible for bringing fresh water from the coast, where the ice forms, out into the ocean. With the freshwater lid broken, more warm water can rise, shrink the sea ice's extent, and in turn ensure that there will be less fresh water in future, Silvano said.

Other experts agree with the paper's findings, describing it as a missing puzzle piece that could explain discrepancies between climate models and real-world data.

"The fact that this change in salinity is counter to what we expect under climate change suggests there are processes at play that we don't fully understand, and that might not be included or well represented in our climate models," Ariaan Purich, an Antarctic climate researcher at Monash University in Australia, told Live Science. Purich suggests that investigating the gaps between the predictions of models and readings like these could provide new insights.

Another missing element is "the kind of observations that provide the information to build the right processes into models," Caroline Holmes, a polar researcher at the British Antarctic Survey, told Live Science. "The Southern Ocean below the surface is chronically underobserved, and there is momentum at the moment building towards two major initiatives, Antarctica InSync and the International Polar Year, that would do just that."

Meanwhile, Silvano and his colleagues will look into what triggered the salinity spike in 2015 and whether this could be considered a tipping point, alongside how the process may influence the world's climate through impacts on the sea ice, ocean circulation and carbon cycling.

"The timeline for these changes to have widespread global consequences is uncertain, but if the current trends continue, we could begin seeing more pronounced effects within a few decades," Silvano said. "Reduced sea ice may enable the release of carbon stored in the Southern Ocean, increasing atmospheric CO₂ — as has occurred in past warm climate periods. This process is not yet fully understood and warrants urgent further investigation."

Instruments flying more than 18 miles (29 kilometers) above Antarctica detected two unexplainable radio pulses coming from below the ice — and these signals seem to defy particle physics.

Researchers determined the radio pulses came from angles around 30 degrees below Antarctica's surface, which the laws of physics theoretically prohibit. Calculations suggest the signals had to pass through thousands of miles of rock to get to the surface; however, scientists expect the pulses to be absorbed by the rock on this journey, rendering them undetectable.

The research team is now looking deeper into what could have caused the unexpected pulses. They ruled out some possible explanations using the Pierre Auger Observatory in Argentina and shared those findings in a study published March 27 in the journal Physical Review Letters.

"It's an interesting problem because we still don't actually have an explanation for what those anomalies are," Stephanie Wissel, a particle physicist and co-author of the study, said in a statement.

Excluding neutrinos

The mysterious pulses were first detected by the Antarctic Impulsive Transient Antenna (ANITA) experiment. ANITA comprises 24 radio antennas attached to a NASA balloon, located near the south pole to avoid signal interference.

Related: Antimatter detected on International Space Station could reveal new physics

The project was designed to capture data about neutrinos — subatomic particles that are especially difficult to study because they lack electric charge and have minimal mass. These elusive characteristics have earned them the nickname "ghost particles".

But the confusing radio signals are "most likely not representing neutrinos," Wissel said. Existing models, she explained, predict that pulses caused by neutrinos would originate from angles very far from 30 degrees under the surface. The new study provides further evidence that neutrinos are probably not involved.

Using complex mathematical models and simulations, the research team also ruled out noise and known particle interactions as sources of the signals. They even examined data from other experiments to see if they observed any interaction that could cause the pulses, to no avail.

Since these observations can't be explained by the Standard Model, the theory that describes subatomic particles, the phenomenon responsible for these pulses could be key to unlocking new scientific understanding.

"More research needs to be done on this," Benjamin Flaggs, a physics graduate student at the University of Delaware and co-author of the study, told Live Science. "There are theorists proposing some beyond-standard-model interactions from different types of particles," he said.

Searching for the cause

If neutrinos aren't responsible for the radio signals, then what is?

Some theories suggest the signals are coming from dark matter — the invisible entity that makes up about 27% of the universe, but which remains poorly understood — Wissel said. But more data is needed before coming to any meaningful conclusion. Wissel favors the theory that the origin of these pulses may be explained by some as-of-yet unknown behavior of radio waves, but there's no evidence to support this guess, either. "So, right now, it's one of these long-standing mysteries," she said.

The Payload for Ultrahigh Energy Observations, a new balloon-based instrument, with advanced levels of sensitivity, is expected to help solve this puzzle by detecting more anomalies, thus providing more data to be scrutinized. "The more data we can get, the better we can get our statistical error," Flaggs said. The instrument will launch from Antarctica in December.

"We haven't discovered everything yet," Flaggs added. "It's exciting for researchers because these are problems that no one else has figured out before."

An elusive species of deep-sea squid has been seen alive for the first time off Antarctica, National Geographic has announced.

Researchers filmed the Antarctic gonate squid (Gonatus antarcticus) drifting through the black waters of the ocean's midnight zone, 7,060 feet (2,152 meters) below the surface, on Dec. 25, 2024.

As first reported by National Geographic, researchers spotted the 3-foot-long (0.9 m) blood-red creature using a remotely operated vehicle (ROV), which had been deployed from the Schmidt Ocean Institute’s research vessel, the R/V Falkor (too). They sent the footage to Kat Bolstad, head of the Lab for Cephalopod Ecology and Systematics at Auckland University of Technology in New Zealand, who confirmed it was an Antarctic gonate squid.

"This is, to the best of my knowledge, the first live footage of this animal worldwide," Bolstad told National Geographic.

Related: Elusive colossal squid finally caught on camera 100 years after discovery in world 1st footage — and it's tiny

Scientists have known about the Antarctic gonate squid for more than 100 years, but they have previously only seen dead specimens caught in fishing nets or beaks that had been preserved in the stomachs of other animals. This is the first time scientists have observed the squid alive and in its natural habitat.

The creature was in the bathypelagic or midnight zone, 3,300 to 13,100 feet (1,000 to 4,000 m) below the ocean's surface. No sunlight can penetrate that far into the ocean, so the midnight zone's only light comes from animals that can illuminate themselves with bioluminescence, according to the National Oceanic and Atmospheric Administration (NOAA).

The squid released a cloud of greenish ink when the ROV approached, potentially startled by the presence of a large, bright vehicle in its environment. The researchers followed the animal for a few minutes, using the ROV's lasers to measure its size, before the squid shot away into the darkness, National Geographic reported.

While researchers couldn't determine the sex or age of the animal, Bolstad confirmed it was an Antarctic gonate squid by observing the presence of a single, large hook on the ends of its two longer tentacles.

"The impressive tentacle hooks are probably used for grasping and subduing prey during ambush predation," Alex Hayward, a senior lecturer in ecology and conservation at the University of Exeter in England who was not involved in the expedition, told National Geographic.

A striking new satellite photo has revealed that the world's largest iceberg is starting to break apart into thousands of smaller pieces as it remains stuck alongside a wildlife refuge in Antarctica. But it could take months, if not years, for the entire slab to disappear.

The "megaberg," dubbed A23a, currently has a surface area of around 1,200 square miles (3,100 square kilometers) — roughly the size of Long Island. It first calved off of the Filchner-Ronne Ice Shelf in 1986, but it became trapped when its underside caught on the seafloor. It remained stranded until January 2023, when it finally began to move away from mainland Antarctica. During this time, it has repeatedly held the title of "world's largest iceberg" as bigger bergs have come and gone, most recently regaining the title in June 2023.

The giant iceberg became trapped again in early 2024 after getting caught in a large ocean vortex. It remained spinning on the spot for several months before eventually breaking free in December 2024 and resuming its journey north through the Drake Passage — also known as the "iceberg graveyard," where large Antarctic icebergs get swept away to their eventual doom.

But in January, it became clear that A23a was on a collision course with South Georgia in the Scotia Sea. By March, the megaberg came to a halt as it grounded on the seafloor around 60 miles (100 kilometers) off the island's southwest coast, where it became trapped for the third — and likely final — time in its lengthy lifespan.

Now, photos from NASA's Aqua satellite have revealed that the edges of A23a are starting to disintegrate, especially along its northern edge, blanketing the surrounding area with icy debris, according to NASA's Earth Observatory. "Thousands of iceberg pieces litter the ocean surface near the main berg, creating a scene reminiscent of a dark starry night," NASA representatives wrote.

Related: See all the best images of Earth from space

The numerous new icebergs appear extremely small compared with A23a. However, "many measure at least a kilometer across and would pose a risk to ships," NASA representatives wrote. The largest piece to break off from the megaberg, which has been dubbed A23c, has an area of around 50 square miles (130 square km) and is currently drifting south (just out of the satellite photo).

This type of iceberg disintegration is known as "edge wasting" and has shrunk A23a by around 200 square miles (520 square km) since it became stuck in March, according to NASA. At this rate, it will likely take several months, if not years, for the berg to fully break apart, assuming larger cracks do not rip it apart first.

However, A23a may not hold its size title for long, because as of May 16, it is only around 12 square miles (31 square km) larger than the next-biggest iceberg, D15A, according to the U.S. National Ice Center.

Wildlife refuge

South Georgia is not inhabited by people, aside from a few dozen researchers who visit throughout the year. However, it is home to an abundance of wildlife, such as seals and seabirds, including more than 2 million penguins, according to BirdLife International.

Having a large iceberg moored just offshore can be problematic for these species, especially for penguins that may have to travel several hundred extra miles around the obstruction to reach their prey, depending on where the iceberg is located. Meltwater coming from trapped bergs can also alter the temperature and salinity of their surroundings.

It is currently unclear how much of an impact A23a is having on the local wildlife. However, the iceberg is quite far off the coast, meaning it will be less disruptive than it could have been. Some researchers have claimed the melting slab could benefit the marine ecosystem by releasing nutrients into the ocean.

This is not the first time that South Georgia has been put under siege by giant icebergs. In 2020, one of the world's previous largest icebergs, A68, became stuck even closer to the island, sparking fears that it could disrupt penguin colonies. However, unlike A23a, it quickly broke up into dozens of sizable chunks after ocean currents ripped it in half, causing it to quickly melt away and thus averting disaster.

As human-caused climate change continues to cause increased melting of Antarctica's ice sheets, many more hefty bergs could soon pass by South Georgia in the coming decades.

Antarctica has gained ice in recent years, despite increasing average global temperatures and climate change, a new study finds.

Using data from NASA satellites, researchers from Tongji University in Shanghai tracked changes in Antarctica's ice sheet over more than two decades. The overall trend is one of substantial ice loss on the continent, but from 2021 to 2023, Antarctica gained some of that lost ice back.

However, this isn't a sign that global warming and climate change have miraculously reversed. Picture a long ski slope with a small jump at the end. That's what a line through the Antarctic ice sheet data looks like when plotted on a graph. While there have been some recent ice gains, they don't even begin to make up for almost 20 years of losses.

Most of the gains have already been attributed to an anomaly that saw increased precipitation (snow and some rain) fall over Antarctica, which caused more ice to form. Antarctica's ice levels fluctuate from year to year, and the gains appear to have slowed since the study period ended at the beginning of 2024. The levels reported by NASA thus far in 2025 look similar to what they were back in 2020, just before the abrupt gain.

Related: What's hiding under Antarctica's ice?

The ice sheet covering Antarctica is the largest mass of ice on Earth. Bigger than the whole of the U.S., the sheet holds 90% of the world's fresh water, according to the Antarctic and Southern Ocean Coalition, an environmental non-governmental organization. Antarctica is also surrounded by sea ice (frozen ocean water), which expands in the winter and retreats to the Antarctic coastline in the summer.

This latest study, published March 19 in the journal Science China Earth Sciences, analyzed data from NASA's Gravity Recovery And Climate Experiment (GRACE) and GRACE Follow-On satellites that have been monitoring this ice sheet since 2002. Studying changes to the sheet is important because any melt releases water into the ocean, which is a major driver of rising sea levels.

The satellite data revealed that the sheet experienced a sustained period of ice loss between 2002 and 2020. The ice loss accelerated in the latter half of that period, increasing from an average loss of about 81 billion tons (74 billion metric tons) per year between 2002 and 2010, to a loss of about 157 billion tons (142 billion metric tons) between 2011 and 2020, according to the study. However, the trend then shifted.

The ice sheet gained mass from 2021 to 2023 at an average rate of about 119 billion tons (108 metric tons) per year. Four glaciers in eastern Antarctica also flipped from accelerated ice loss to significant mass gain.

"This isn't particularly strange," said Tom Slater, a research fellow in environmental science at Northumbria University in the U.K. who wasn't involved in the study. "In a warmer climate the atmosphere can hold more moisture — this raises the likelihood of extreme weather such as the heavy snowfall which caused the recent mass gain in East Antarctica," he told Live Science in an email.

A 2023 study documented Antarctica's unprecedented mass gain between 2021 and 2022. That study, written by many of the same authors behind the new study, found that a high precipitation anomaly was responsible for the gain in ice. The latest study suggests that the trend continued until at least 2023.

Slater noted that researchers expect the ice gains to be temporary.

"Almost all of Antarctica's grounded ice losses come from glaciers elsewhere which are speeding up and flowing into the warming ocean," Slater said. "This is still happening — while the recent snowfall has temporarily offset these losses, they haven't stopped so it's not expected this is a long-term change in Antarctica's behaviour."

A warming world

Climate change doesn't mean that everywhere on Earth will get hotter at the same rate, so a single region will never tell the whole story of our warming world. Historically, temperatures over much of Antarctica have remained relatively stable, particularly compared to the Arctic, which has cooked four times faster than the rest of the globe. Antarctica's sea ice has also been much more stable relative to the Arctic, but that's been changing in recent years.

In 2023, Antarctic sea ice hit record lows, which researchers concluded was extremely unlikely to happen without climate change. Meanwhile, global sea ice cover is consistently dropping to record lows or near-record lows, while global temperatures are consistently at record or near-record highs.

In 2015, world leaders signed the Paris Agreement, an international treaty promising to limit global warming to preferably below 2.7 degrees Fahrenheit (1.5 degrees Celsius) and well below 3.6 F (2 C). However, that first promise is on the line: April 2025 was the 21st out of the last 22 months to breach the 2.7 F limit, according to the European Union's Copernicus Climate Change Service.

From above, Antarctica might seem like a cold, flat and desolate landscape — and it certainly is. But beneath the ice sheet lies an entire hidden world: Scientists have discovered diverse biomes, hidden rivers and lakes, mountains and valleys, primordial bacteria, and even the remnants of ancient ecosystems.

Almost 90% of Antarctica's land is covered in a thick layer of ice — around 1.3 miles (2.2 kilometers) deep, on average — and it's been that way for around 34 million years. Yet researchers have only scratched the surface of what lies under the mysterious continent.

"It's so exciting to dive into these past worlds and to understand how this continent evolved over time, and what that means," Johann Klages, a sedimentologist at the Alfred Wegener Institute of Germany who studies climate history in Antarctica, told Live Science. "What does it tell us about our own existence on this planet?"

In his research, for instance, Klages discovered the first amber fossil ever found in Antarctica — a remnant of the ancient temperate rainforest that covered the continent over 90 million years ago. Klages believes there's likely more amber to be found in future expeditions, too.

Antarctica is also home to over 400 subglacial lakes. The largest, Lake Vostok, lies under 2.5 miles (4 km) of ice near Russia's Vostok Station. "And what's in there? Probably microbes," Klages said. "But also," because of the immense pressure of the ice, "probably life that isn't found anywhere else on Earth."

Related: Will Antarctica ever be habitable?

A complex system of rivers funnels water in and out of those lakes, according to research led by Christine Dow, a glaciologist at the University of Waterloo in Canada who has used radar imaging to see what lies beneath the ice's surface.

If you're having a hard time picturing an entire body of water underneath an ice sheet, just think of a river you would see flowing into a lake and toward the ocean — "but then you just add on 4 kilometers [2.5 miles] of ice on top," Dow explained. That ice makes the water behave a bit strangely. "You can actually have water flowing uphill underneath the Antarctic ice," she told Live Science. "It's not as defined by gravity."

A lot of what lies under the ice is not as exciting, however. "The vast majority of what's underneath the ice is just rock," Klages said. "It's just crystalline bedrock, crystalline basement, granite."

One of the most important elements is the very large planes of soggy sediment beneath some parts of the ice, Dow said. "Those are the areas that are flowing really fast into the ocean, because essentially the ice is just floating on top of this slurry of wet sediment," she explained. "It's not as aesthetic-sounding as the mountains and the valleys, but it's very important for understanding how the ice is behaving."

Knowing what's going on underneath the ice sheet is important for predicting what will happen when it melts, according to Dow and Klages.

There are entire areas of the Antarctic, like much of West Antarctica, that are below sea level because of the thickness of the ice sheet. "There's no ocean there right now, because the ice is taking up all of the space," Dow said.

If you imagine that the ice is in a bowl, it's currently right at the rim. But once the ice starts to retreat, it will move back into the bowl. And because ice is less dense than water, it will become more buoyant. At that point, the ice is "floating like a giant ice cube," Dow said.

Once all of the area below sea level becomes filled by the ocean, the ice will become more unstable and will break up, contributing even more to sea-level rise. "So the moment when that ice starts retreating from the rim is really critical," Dow said. "And we're at that point right now.

"It's a pretty unstable place, the Antarctic," she added. "It's beautiful, it's vast, it's mysterious — but it's also really dangerous."

Antarctica quiz: Test your knowledge on Earth's frozen continent

Dramatic ice melt due to climate change may move the locations of Earth's geographic poles in the coming years, a new study finds.

As ice sheets melt and ocean mass gets redistributed around the planet, Earth's geographic North and South poles could shift up to 89 feet (27 meters) by 2100 as the planet's axis of rotation changes, according to the study, published March 5 in the journal Geophysical Research Letters. The shift could affect satellite and spacecraft navigation, the researchers said.

As Earth spins, changes in the distribution of the planet's mass cause it to wobble on its axis like a top. Many of these wobbles are regular and predictable — some are due to regular changes in atmospheric pressure and ocean currents, while others result from interactions between the core and the mantle.

Recent studies have suggested that melting ice sheets and glaciers could also affect this mass distribution and shift Earth's poles. In the new study, researchers at ETH Zurich used both the movement of the poles from 1900 to 2018 and projections of ice sheet melt to predict how far the poles might move under different human-caused climate change scenarios.

The North Pole could shift westward by more than 89 feet by 2100 under the worst-case greenhouse gas emissions scenario, the team found. Under a more optimistic emissions scenario, the pole could still shift as much as 39 feet (12 m) relative to its location in 1900. Meltwater from the Greenland and Antarctic ice sheets played the largest role in the simulations, followed by glacier melt.

"This effect is somewhat surpassing the effect of glacial isostatic adjustment, which is the effect of solid Earth rebound after the termination of the last ice age," study co-author Mostafa Kiani Shahvandi, an Earth scientist now at the University of Vienna, told Live Science.

In other words, land at the surface of the crust sunk under the weight of ice age glaciers and rose when they melted, changing the weight distribution in Earth's crust and shifting the poles. "This means that what humans have done has somewhat shifted the pole more than the effect of ice ages," Kiani Shahvandi said.

Causing confusion for sat-nav

A shift in Earth's rotational axis could disrupt satellite and spacecraft navigation, Kiandi Shahvandi said. Scientists map a spacecraft's location in part using Earth's rotation axis as a reference. If that axis shifts over time, it could become harder to pinpoint the spacecraft's exact location.

Future work could involve examining paleoclimate data to determine how much the poles have shifted over millions of years during past episodes of natural climate change. According to Kiandi Shahvandi, this would help reveal the true scale of human impact on the poles' movement.

This story was originally published on April 8.

The Wilkes Land crater is a hole in the bedrock beneath East Antarctica's ice sheet measuring 315 miles (510 kilometers) across. Researchers have been trying to explain its existence since the 1960s, and the most recent evidence suggests it was born from a cataclysmic meteorite impact.

The crater was first detected as a huge dent in Earth's gravitational field. Initial ground-based seismic and gravity surveys already indicated that the crater was huge — around 150 miles (240 km) across — but newer techniques reveal that it is likely more than double this size.

According to a 2018 study, the Wilkes Land crater sits about 1 mile (1.6 km) beneath the surface of Antarctica's ice sheet. The study showed the crater in more detail than ever before and examined its potential link with southern Australia, which was connected to East Antarctica until around 35 million years ago. While the origin of the crater remains uncertain, the results of the study suggest the event that created the hole likely occurred before the continents separated.

Researchers have proposed several explanations for the Wilkes Land crater, including that it could be a volcanic structure, a sedimentary basin, a deeply eroded valley or a meteor impact crater, according to a 2015 paper. For that paper, scientists used satellite remote sensing techniques to map the crater and determine its physical characteristics. In the middle of the hole in Earth's gravitational field, known as a negative gravity anomaly, they found a positive gravity anomaly, with the ice sheet filling the gap around this central peak like a huge, frosty donut.

Related: Scientists create new map showing ice-free Antarctica in more detail than ever before

The central peak is likely a structure known as a mass concentration, or a "mascon," according to the study. Mascons can occur within meteor impact structures due to the meteor crashing through Earth's crust and affecting the mantle beneath. Following the impact, the mantle may recoil and form a dense plug, resulting in a positive gravity anomaly, the study authors wrote.

The Wilkes Land crater and its mascon aren't perfectly circular and instead form a U-shape, according to the 2018 study, whose results support the conclusion that the crater was caused by a meteor impact. The northern side of the crater is fragmented, perhaps as a result of tectonic processes that ripped Australia and Antarctica apart, the authors noted. Parts of the crater are clearly visible in southern Australia, they added.

If the Wilkes Land crater is an impact crater, then it "would be the greatest impact crater known" on Earth in terms of its size, the authors wrote.

In the 2015 study, researchers found that the crater's diameter matches the speed and size of space rocks that regularly crashed into Earth during its early history between 4.1 billion and 3.8 billion years ago. "The WLA [Wilkes Land Anomaly] could have been created by such bolides," they wrote in the study.

"Nonetheless, because of the constraints imposed by the overlying continental ice sheet, [...], we believe that the other explanations for the subglacial structure remain viable," they added.

Discover more incredible places, where we highlight the fantastic history and science behind some of the most dramatic landscapes on Earth.

Antarctica quiz: Test your knowledge on Earth's frozen continent

A gigantic iceberg that broke off of an Antarctic glacier has revealed a thriving never-before-seen ecosystem in the depths beneath.

The iceberg A-84, which is roughly the size of Chicago, calved from Antarctica's George VI Ice Shelf on Jan. 13, 2025.

After receiving news of the iceberg’s movement from satellite imagery, scientists aboard the Schmidt Ocean Institute's research vessel Falkor quickly hurried to the site. Just 12 days later, they arrived to find a never-before-seen ecosystem filled with giant sponges, fish, enormous sea spiders and octopuses exposed to the open air for the first time.

"We seized upon the moment, changed our expedition plan, and went for it so we could look at what was happening in the depths below," expedition co-chief scientist Patricia Esquete, a marine biologist at the University of Aveiro in Portugal, said in a statement. "We didn't expect to find such a beautiful, thriving ecosystem. Based on the size of the animals, the communities we observed have been there for decades, maybe even hundreds of years."

What lies beneath Antarctica's roughly 500 feet (150 meters) of ice is scarcely known, but scientists have suspected that it is filled with a gigantic network of rivers, lakes and estuaries. Yet it wasn't until very recently that scientists discovered that this hidden underworld harbored life.

Related: Scientists create new map showing ice-free Antarctica in more detail than ever before

Without sunlight or nutrients raining down from above, this life is likely sustained by deep-sea ocean currents that slip beneath the surface of the shelf, although scientists are unsure if this is the only mechanism at play.

To investigate the once-hidden biome, the scientists deployed a remotely operated submarine (named SuBastian), which — due to the thick ice blocking off GPS signals — navigated using sound waves to arrive at the ocean floor.

Once there, the submarine collected biological and geological samples from among the region's coral and sea sponges. Some of these creatures' enormous sizes suggested they'd been growing for centuries. The researchers also deployed other autonomous vehicles to study how meltwater is affecting the region.

"The science team was originally in this remote region to study the seafloor and ecosystem at the interface between ice and sea," Jyotika Virmani, executive director of the Schmidt Ocean Institute, said in the statement. "Being right there when this iceberg calved from the ice shelf presented a rare scientific opportunity. Serendipitous moments are part of the excitement of research at sea — they offer the chance to be the first to witness the untouched beauty of our world."

Antarctica quiz: Test your knowledge on Earth's frozen continent

The Drake Passage is an ocean channel between the southern tip of South America and the West Antarctic Peninsula. Named after the 16th-century explorer Sir Francis Drake, it is notorious for whipping up wild storms and monster waves up to 80 feet (25 meters) tall.

The passage is "the most dreaded bit of ocean on the globe," Alfred Lansing wrote in his 1959 book "Endurance: Shackleton's Incredible Voyage to the Antarctic." At around 600 miles (965 kilometers) wide, the channel is relatively narrow compared with the ocean around it, meaning currents speed up as they are forced through the passage. The same goes for southern winds, which blow unimpeded from west to east around Antarctica before they reach the Drake Passage.

As winds funnel through the passage, they whisk up huge waves, some of which can be dangerous — and even deadly — for passengers on boats making the 48-hour-long crossing. In the best case, the waves make for a bumpy ride, known as the "Drake shake."

"It's always interesting when you go to dinner and they put sticky mats on all the tables to make sure your plates and things don't slide around," Karen Heywood, a professor of physical oceanography at the University of East Anglia in the U.K. who sailed through the Drake Passage in 2024, told National Geographic.

Related: Mount Washington: Home to 'the world's worst weather' with record wind speeds of 231 mph

The Drake Passage is a "melting pot" of currents from the Atlantic, Pacific and Southern oceans, Heywood said. The waters are so turbulent that the layers which normally make up the seas mix together, meaning the passage draws a lot more carbon down into its depths than other parts of the ocean do.

The world's oceans lock away more than 30% of the carbon humans emit into the atmosphere every year, and the Drake Passage could be one of a handful of places where this activity is particularly pronounced, National Geographic reported.

The passage also keeps Antarctica cold, because it cuts off warm air that would otherwise blow south from South America. Research suggests that when the Drake Passage opened between 49 million and 17 million years ago, it triggered significant cooling in Antarctica and contributed to the growth of giant ice sheets on the continent.

The temperature drop as you traverse the passage is noticeable even for people on ships, Alberto Naveira Garabato, a professor of physical oceanography at the University of Southampton in the U.K., told National Geographic. "Suddenly you are in this icy world," Naveira Garabato said.

So, while extreme winds and currents inside the passage create terrifying conditions for passengers, they also help to maintain Antarctica's frigid climate — although climate change is slowing the system.

Were it not for the Drake Passage and its wild weather, the frozen continent would likely hold much less ice than it currently does.

Discover more incredible places, where we highlight the fantastic history and science behind some of the most dramatic landscapes on Earth.

Scientists have captured stunning video of a dinner-plate-size sea spider crawling on the seafloor off the South Sandwich Islands, a chain of volcanic islands near Antarctica in one of the most remote areas of the world.

Sea spiders, also known as pycnogonids, are distant cousins of the creepy-crawly arachnids we see scuttling about on land. These creatures can have leg spans of up to 20 inches (51 centimeters) — nearly double those of the largest land spiders, whose leg spans top out at around 12 inches (30 cm).

According to the Schmidt Ocean Institute, which shared the footage, the spider's massive size is a result of deep-sea gigantism, the tendency for deep-sea creatures to grow significantly larger than their shallow-water relatives. In this case, the pycnogonid was filmed at a depth of 6,903 feet (2,104 meters).

Related: 32 truly bizarre deep-sea creatures

"Immense pressure and frigid temperatures, while insurmountable obstacles to land-lovers like humans, allow some animals to have very slow metabolisms and the ability to reach gargantuan proportions," Schmidt Ocean Institute representatives wrote in a Facebook post.

Larger animals can also move faster and farther to find food or to locate a mate, which is important when both are scarce.

Deep-sea gigantism is particularly prevalent toward the poles, where freezing temperatures facilitate slower metabolisms. Schmidt Ocean Institute representatives described sea spiders as both "abundant" and "abundantly large" in polar regions.

There are roughly 1,500 species of sea spider known to science and likely many more yet to be discovered, according to the post. Sea spiders inhabit oceans around the world and range just a few millimeters to the size of a serving platter. The species of spider in the video from the Schmidt Ocean Institute has not been specified.

The largest members of this group are usually found at depths between 7,200 and 13,100 feet (2,200 to 4,000 m), according to the Monterey Bay Aquarium Research Institute.

Instead of spinning webs or creating burrows as land spiders do, sea spiders use a specialized tube-like mouth structure, called a proboscis, to slurp up prey such as sea anemones, jellies and other invertebrates.

This latest footage was taken by remotely operated vehicle pilots as part of the Schmidt Ocean Institute's South Sandwich Islands expedition, a mission to locate and describe new species in these frigid waters. According to the institute, scientists have discovered only 10% of ocean life.

Scientists have unveiled the most detailed map yet of the landscape hidden beneath Antarctica's ice.

The high-resolution map reveals what the frozen continent looks like beneath its miles-thick blanket of ice and snow, and will help researchers predict how Antarctica might evolve in a fast-warming climate.

"Imagine pouring syrup over a rock cake [or a chocolate chip cookie, if that's more familiar to you] — all the lumps, all the bumps, will determine where the syrup goes and how fast," Hamish Pritchard, a glaciologist at the British Antarctic Survey (BAS) and the lead author of a new study outlining the research, said in a statement.

The same process will occur in Antarctica if a significant amount of the ice sheet melts, Pritchard said. "Some ridges will hold up the flowing ice; the hollows and smooth bits are where that ice could accelerate," he said.

Related: When was the last time Antarctica was ice-free?

Bedmap3 builds on two previous studies that digitally stripped Antarctica of its ice. The new map incorporates all of the data used for Bedmap1 and Bedmap2 — including measurements gathered by planes, satellites, ships and even dog-drawn sleds. But the team also sourced an extra 52 million data points to refine these previous results, according to the study, published March 10 in the journal Scientific Data.

In total, more than six decades' worth of data was compiled to construct Bedmap3, the researchers said in the statement. "This is the fundamental information that underpins the computer models we use to investigate how the ice will flow across the continent as temperatures rise," Pritchard said.

The new map is color coded to show the height of Antarctica's bedrock above sea level, highlighting the continent's tallest mountains and deepest valleys. The topography is revealed in the finest detail yet, providing new insight into understudied areas, including around the South Pole, according to the statement.

The researchers used radar, seismic and gravity measurements to map the bedrock and estimate the thickness of the ice sheet above it. Against their expectations, they found that the place with the thickest ice in Antarctica is an unnamed canyon in Wilkes Land, a district in the east of the continent.

Previous surveys placed Antarctica's thickest ice in the Astrolabe Basin in Adélie Land. The difference in ice thickness between the two areas is small: The Astrolabe Basin has a thickness of around 2.9 miles (4.7 kilometers), while Wilkes Land is almost 3 miles (4.8 km) thick, according to the study.

The new research also reveals, in unprecedented detail, the shape of the ice sheet and ice shelves that float around the fringes of the continent.

"In general, it's become clear the Antarctic Ice Sheet is thicker than we originally realized and has a larger volume of ice that is grounded on a rock bed sitting below sea level," study co-author Peter Fretwell, a mapping specialist and geographic information officer at the BAS, said in the statement.

Although thickness in itself is not a problem, the fact that much of the ice sits below sea level is concerning, because relatively warm seawater can flood into the ice sheet, Fretwell said. "This puts the ice at greater risk of melting," he added.

"What Bedmap3 is showing us is that we have got a slightly more vulnerable Antarctica than we previously thought," Fretwell added.

Antarctica quiz: Test your knowledge on Earth's frozen continent

Melting Antarctic ice is slowing Earth's strongest ocean current, according to a new study.

The influx of cold meltwater could slow the Antarctic Circumpolar Current by up to 20% by 2050, researchers reported March 3 in the journal Environmental Research Letters. The slowdown could affect ocean temperatures, sea level rise and Antarctica's ecosystem, the team said.

The Antarctic Circumpolar Current, which swirls clockwise around Antarctica, transports around a billion liters (264 million gallons) of water per second. It keeps warmer water away from the Antarctic Ice Sheet and connects the Atlantic, Pacific, Indian and Southern oceans, providing a pathway for heat exchange between these bodies of water.

Climate change has caused Antarctic ice to melt rapidly in recent years, adding an influx of fresh, cold water to the Southern Ocean. To explore how this influx will affect the Antarctic Circumpolar Current's strength and circulation, Bishakhdatta Gayen, a fluid mechanist at the University of Melbourne in Australia, and his colleagues used Australia's fastest supercomputer and climate simulator to model interactions between the ocean and the ice sheet.

Related: Are Atlantic Ocean currents weakening? A new study finds no, but other experts aren't so sure.

Fresh, cold meltwater likely weakens the current, the team found. The meltwater dilutes the surrounding seawater and slows convection between surface water and deep water near the ice sheet. Over time, the deep Southern Ocean will warm as convection brings less cold water from the surface. Meltwater also makes its way farther north before sinking. Together, these changes affect the density profile of the world's oceans, which drives the slowdown.

Such a slowdown could allow more warm water to reach the Antarctic Ice Sheet, thereby exacerbating the melting that's already been observed. In addition to contributing to sea level rise, this could add even more meltwater to the Southern Ocean and weaken the Antarctic Circumpolar Current further.

The Antarctic Circumpolar Current also acts as a barrier against invasive species by directing non-native plants — and any animals hitching a ride on them — away from the continent. If the current slows or weakens, this barrier could become less effective.

"It's like a merry-go-round. It keeps on moving around and around, so it takes a longer time to come back to Antarctica," Gayen said. "If it slows down, what will happen is, things can migrate very quickly to the Antarctic coastline."

It's difficult to say when we'll start to feel the effects — if we haven't started feeling them already. The Antarctic Circumpolar Current hasn't been monitored very long because it's in such a remote location, Gayen told Live Science. To better differentiate warming-induced changes from baseline conditions, "we need a long-term record," he said.

The effects of the slowdown will be felt even in other oceans. "This is where the ocean heart sits," Gayen said. "If something stops there, or something different is happening, it's going to impact each and every ocean circulation."

Antarctica quiz: Test your knowledge on Earth's frozen continent

After months on the move, the world's largest iceberg, A23a, has run aground off the remote British island of South Georgia, representatives from the British Antarctic Survey (BAS) reported on Tuesday (Mar. 4).

The megaberg, which is roughly the size of Rhode Island, struck shallow waters 50 miles (80 kilometers) from the South Atlantic wildlife haven, the BBC reports, and researchers are keenly observing what it will do next.

"In the last few decades, the many icebergs that end up taking this route through the Southern Ocean soon break up, disperse and melt," Andrew Meijers, an oceanographer at the BAS, said in a statement. "It will be interesting to see what will happen now."

A23a, nicknamed the "queen of icebergs," first broke off from Antarctica's Filchner Ice Shelf in 1986. However, it remained tethered to the seabed for more than three decades before it finally began to break free in 2020, according to the BAS.

In 2024, the icy colossus then got stuck again, spinning in one spot for several months just north of the South Orkney Island. But in December 2024 it broke free once more and continued its journey northwards.

When A23a's trajectory towards South Georgia first became apparent in January, experts feared a collision could be catastrophic for the large colonies of penguins, seals and other marine wildlife that live there.

Related: 45-mile-long iceberg slams into penguin refuge in Antarctica, almost causing ecological disaster

If the megaberg stays grounded, Meijers said it is unlikely to pose a significant threat to the local wildlife. But if it moves closer to the island or breaks apart, "it could interrupt their pathway to feeding sites and force the adults to expend more energy to travel around it," he said. "This could reduce the amount of food coming back to pups and chicks on the island, and so increase mortality."

Similar fears were raised in 2020, when the previous world's largest iceberg, A68a, came perilously close to grounding right next to South Georgia before it was eventually ripped apart into many smaller pieces by ocean currents.

However, there could also be an upside to the recent iceberg grounding: "If the berg is stimulating ocean productivity, this could actually boost populations of local predators like seals and penguins," Meijers said.

As well as stirring up nutrients from the ocean floor, megabergs also contain a vast amount of nutrients locked away in their ice. "It's like dropping a nutrient bomb into the middle of an empty desert," Nadine Johnston, a marine ecologist at the British Antarctic Survey, told BBC.

However, Meijers added that, as the berg disintegrates, it might pose a threat to local sailors and fishermen. "Commercial fisheries have been disrupted in the past however, and as the berg breaks into smaller pieces, this might make fishing operations in the area both more difficult and potentially hazardous."

BAS will continue to monitor the effects of this iceberg on the surrounding ecosystem.

Researchers in Australia have discovered fossils of two enormous predators that lived alongside one another, upending ideas about how the ancient ecosystem operated down under 120 million years ago. This cache of fossils included the oldest large megaraptor ever found.

Megaraptorids were a group of fearsome predators in the Cretaceous period (145 million to 66 million years ago). They lived in the ecosystems of Australia and South America, which were joined together via Antarctica as part of a massive southern landmass called Gondwana.

Study lead-author Jake Kotevski, a paleontology doctoral candidate at the Museums Victoria Research Institute and Monash University in Australia, described megaraptorids as a "hands first predator" with muscular forearms and long, curved claws for catching prey — they effectively bring their prey in for a "hug of death," he said in a video released by Museums Victoria.

The fossils discovered by Kotevski and his colleagues belonged to an unspecified 120 million-year-old megaraptorid that was 20 to 23 feet (6 to 7 meters) long — making it one of the largest theropods (a bipedal group of mostly meat-eating dinosaurs) ever discovered in Australia. It also predates megaraptorids in South America by around 30 million years.

In the new study, published Feb. 19 in the Journal of Vertebrate Paleontology, researchers also identified fossils from another group of large, predatory dinosaurs called Carcharodontosauria, which are also found in South America but have never been identified in Australia before.

The carcharodontosaur fossils suggest that in Australia, these dinosaurs grew up to 13 feet (4 m) long, which is significantly shorter than their counterparts in South America, which grew up to 43 feet (13 m).

In other words, the roles of the two predatory dinosaurs seem to have been reversed in Victoria, with megaraptorids acting as the larger apex predators and carcharodontosaurs acting as smaller, secondary predators. Australia's unique Cretaceous ecosystem therefore had an "upside-down" dynamic, according to a statement released by Museums Victoria.

Related: What if a giant asteroid had not wiped out the dinosaurs?

The newly identified fossils were found in what were the banks of a large river, like the modern-day Ganges or Amazon, Kotevski told Live Science in an email. Southern Australia was close enough to the South Pole that it was within the Antarctic Circle during the Cretaceous, although the region was much warmer then than it is today.

The team identified the fossils, collected from the upper Strzelecki rock formation on the coastline of Victoria in southern Australia between 1988 and 2022, with modern 3D imaging techniques, including micro-computed tomography. The technique involves taking X-rays of an object as it rotates 360 degrees so that it can be studied in greater detail.

The fossils revealed that giant megaraptorids and carcharodontosaurs were living near the river, which Kotevski said was situated within a vast rift valley created as Australia pulled away from Tasmania and Antarctica.

"In the Antarctic circle, it has been proposed that Cretaceous [Victoria] experienced long periods of dark/light that the poles experience today," Kotevski said. "Thick forests lined this fast flowing river, where [a] myriad [of] small dinosaurs thrived, seemingly dominated by our … apex predator megaraptorid."

The discoveries add to evidence that dinosaurs were traveling across Antarctica to move between South America and Australia during the middle of the Cretaceous, according to the study. However, Kotevski noted that researchers still have a lot more to learn about the Australian dinosaur ecosystem.

"More discovery, collection and research is fundamental to further unlocking these secrets and building a picture of how these animals looked, differed, and behaved within their environment," Kotevski said.

Lake Vostok is a giant lake in Antarctica that is similar in size to North America's Lake Ontario. But unlike Lake Ontario, Lake Vostok sits beneath more than 2 miles (3 kilometers) of wind-blown snow and ice.

Once an enormous surface lake, Lake Vostok became buried at least 15 million years ago, with some estimates suggesting it has been continuously covered for much longer — 20 million years or more. As a result of being cut off from light and the atmosphere for so long, the lake harbors a unique ecosystem of extremophiles — creatures that have evolved to thrive in extreme conditions.

Related: Scientists peered into a secret Antarctic lake hidden beneath the ice — and uncovered a never-before-seen ecosystem

Lake Vostok is about 150 miles (240 km) long and 30 miles (50 km) wide. It is the biggest of Antarctica's more than 400 subglacial lakes, which are scattered across the continent because low levels of geothermal heat melt the base of the ice sheet.

The lake is located near Russia's Vostok research station, roughly 800 miles (1,300 km) from the South Pole. Although scientists have occupied Vostok since 1957, they had no idea the lake existed until the 1960s, when a Russian geographer and pilot first noticed the flat, relatively smooth expanse of ice above it from the air.

In 1993, researchers found the lake with satellite-based radar technology capable of penetrating the ice. And in 2012, Vostok scientists finally succeeded in a years-long effort to drill down to the lake through the ice.

Lake Vostok is about 0.6 miles (1 km) deep at its south end and comparatively shallower at its north and southwest corners. Researchers mapped the bottom of the lake and found that the deep and shallow areas are separated by a ridge, which they think might be peppered with hydrothermal vents similar to those in the Pacific Ocean.

The lake's only source of water is the ice sheet above it. The water temperature hovers around 27 degrees Fahrenheit (minus 3 degrees Celsius), but it remains liquid thanks to the crushing pressure of the overlying ice sheet, which lowers the freezing point of the water.

Countless species of microbes inhabit the lake, including marine lifeforms that suggest the water body was once connected to the ocean. Researchers sampled a layer of frozen water called accretion ice that sits on top of the lake and found it contains DNA from more than 3,500 organisms, including fungi and bacteria commonly found in the digestive tracts of fish.

Due to the lack of light blocking photosynthesis, these organisms have evolved to feast on minerals in the water and chemicals produced in the bedrock. Researchers think that further studying them could provide clues about life on other planets and moons, including Jupiter's icy moon Europa.

Discover more incredible places, where we highlight the fantastic history and science behind some of the most dramatic landscapes on Earth.

Stunning new footage captures the moment adult orcas carefully teach their calves how to hunt, demonstrating how to push a seal off a bit of ice before getting the young to give it a go themselves.

The clip shows a group of seven orcas — four adults and three calves — as they circle a seal on a tiny chunk of ice in western Antarctica’s Marguerite Bay. The lesson, which lasted over an hour, was filmed for the new PBS show "Nature: Expedition Killer Whale," which follows a remarkable group of pack ice orcas (Orcinus orca) that live off the coast of Antarctica.

"The biggest surprise was the careful, measured way in which the females kept the seal corralled close to the piece of ice without fatally injuring it, so that it would climb back out onto the ice," Leigh Hickmott, a whale biologist and science advisor for the show, who observed the encounter from a boat nearby, told Live Science in an email.

"This allowed the females to show the calves a number of different approaches to gain access to the seal, all in one teaching session," he said. The hunting techniques they taught the calves included "wave washing, tipping the ice, bubble blowing to flush the seal from under the ice and taking hold of the seal by its hind flippers to prevent injury from its teeth."

Related: Boat-ramming orcas may be using yachts as target practice toys, scientists suggest

In the footage, a female orca leads the lesson, demonstrating how to pull the seal off the ice by its tail, as the calves watch and learn. She lets the seal escape, and after it jumps back on the ice, the calves take turns practicing the technique — a behavior that's repeated over and over.

Orcas are highly intelligent apex predators. They are social, living in family pods, and hunt in packs. They're among the few species known to actively teach their young (and one another) different skills, which can result in innovative new behaviors.

The orcas observed in the clip, known as type B1 orcas, are known for their "wave-washing" hunting technique, where the pod works together to create large waves that knock seals from the safety of ice floes into the water.

The PBS show also reveals the first recordings of these orcas' calls to each other as they search for prey, coordinate hunts and share their catch.

Hickmott said the teaching sequence highlights the cultural transmission of knowledge between orcas and shows their ability to solve complex problems through teamwork.

"Remembering past experiences and honing techniques builds their effectiveness as predators and that by regularly allowing young inquisitive calves to participate in order to learn, they strengthen the pod's future capabilities and likelihood of survival," he said.

"Nature: Expedition Killer Whale" premieres on Wednesday, Feb. 12 at 8/7c.

► How to watch 'Expedition Killer Whale' — TV and streaming details for orca documentary

Orca quiz: Will you sink or swim?

An extensive model of the Antarctic ice sheet is helping researchers peer deep beneath the ice to reveal the continent's hidden plumbing.

Scientists used computer models to predict how water flows under the entire Antarctic ice sheet, which dictates where and how quickly glaciers move toward the ocean. The findings, published Dec. 29, 2024 in the journal Geophysical Research Letters, will improve predictions of ice sheet stability and future sea level rise.

Current models predict that ice melt from Antarctica could raise sea levels up to 12 inches (30 centimeters) by 2100. Some of this melt comes from ice sliding from the continent's bedrock into the ocean. Liquid water beneath the ice sheet can lubricate the ice, similar to sliding a glass across a wet countertop.

But the extent of this lubrication isn't uniform across the ice sheet — it depends on the weight of the ice and the depth and pressure of the water beneath it. Understanding how these factors vary is important for accurately predicting how much ice will flow into the ocean, and how quickly it will move. While models of smaller individual areas account for the effects of water at the base of the ice sheet, the new study is the first to incorporate it for the whole continent.

Related: Never-before-seen shapes up to 1,300 feet long discovered beneath Antarctic ice

To simulate how subglacial water affects glacier motion, the researchers combined two existing models: the Glacier Drainage System Model, which simulates the way water flows under ice sheets; and the Ice-sheet and Sea-level System Model, which predicts how the ice sheet will flow and change in response to various factors, such as temperature.

The combined model "allows us to identify where water is underneath the ice, or model where the water would be underneath the ice, where it's particularly thick and the pressures are high enough to enable the ice to slide and to flow faster," Neil Ross, a geophysicist at Newcastle University in the U.K. who was not involved in the new study, told Live Science.

The researchers modeled the effective pressure at the base of the ice — the difference between the weight of the ice and the water pressure beneath it. "As that approaches zero, we're approaching the situation where the ice is basically free, floating on the base of water," Rupert Gladstone, a computational glaciologist at the University of Lapland in Finland who was not involved in the research, told Live Science.

The model revealed that the lowest effective pressures are in the interior of the continent and beneath outlet glaciers along the edge of the ice sheet, meaning the ice flows fastest in these regions. Meanwhile, floating ice shelves around the edge of the continent slow ice flow into the ocean. If these ice shelves melt, more ice could flow from the bedrock into the ocean and contribute to sea level rise, the authors wrote.

The model also accurately predicted the locations of known subglacial lakes in western Antarctica. In addition, it predicted the locations of large channels beneath the ice where subglacial water flows into the ocean. Many of these locations align with areas of the ice shelf that are known to melt quickly, suggesting that fresh water entering the ocean from these channels impacts melt rates.

Further studies in Antarctica could look for these features in areas predicted by the model. "It's enabled us to identify where future field observations might be required," Ross said. Field studies could help refine the model and help scientists better understand how subglacial water affects ice flow, Ross added.

Test your knowledge of Antarctica

Scientists in Antarctica have discovered what may be the oldest modern bird ever found. The 69 million-year-old fossil could finally put a longstanding debate about the origin of modern birds to rest.

The nearly complete skull belongs to Vegavis iaai, a waterfowl species believed to be the ancient relative of modern-day ducks and geese. The species lived at the same time as dinosaurs like Tyrannosaurus rex and may have survived the end-Cretaceous mass extinction, the new study suggests.

Study co-author Julia Clarke, a paleontologist at the University of Texas, Austin reported the first V. iaai fossil found on Vega Island in Antarctica in 1992. The fossil was around 66 million to 68 million years old. She proposed that the species is linked to modern birds, especially waterfowl. But not everyone was convinced as scientists were missing a key piece of the puzzle — the creature's skull.

"[The initial fossil] was just a completely different part of the skeleton. And when it comes to birds, the skull has a lot of phylogenetic or informative characteristics that tell you what it is," study co-author Patrick O' Connor, an evolutionary biologist at Ohio University, told Live Science.

Related: How did birds survive the dinosaur-killing asteroid?

The new V.iaai fossil, estimated to be 68 million to 69 million years old, was found during an expedition in 2011, but has only now been analyzed. The study was published Wednesday (Feb. 5) in the journal Nature.

The discovery of the new skull enabled scientists to learn more about this species and how it fits in the bird family tree. They found that, unlike pre-modern birds that existed during the Jurassic and Cretaceous periods (201.3 million to 66 million years ago), V. iaai has features that are similar to birds that exist today — including a brain shape typical of modern birds, and a unique bone in the upper beak. The upper beak of most pre-modern birds is made of a single bone, called the maxilla, with a little bit of another type of bone, pre-maxilla, at the tip.

"When we looked at the Vegavis, it's the pre-maxilla all the way. The maxilla is tiny, which is exactly what we expect from modern birds," study co-author Christopher Torres, a paleontologist at The University of the Pacific in Stockton, California, told Live Science.

Using a 3D reconstruction, the scientists showed that the bird had a long, narrow beak enhanced with powerful jaw muscles, much like modern diving birds use to catch fish.

"Seeing how specialized the skull was, for me, the most impactful," Juan Benito Moreno, a paleontologist at the University of Cambridge who was not involved in the study, told Live Science. "It was surprising to see an incredibly niche ecological feature so early in the evolution."

The giant asteroid that hit Earth at the end of the Cretaceous period (145 million to 66 million years ago) drove all nonavian dinosaurs to extinction. Landfowls (Galliformes) and waterfowls (Anseriformes) were among the earliest modern birds that existed in the age of dinosaurs.

While rapid evolution took place after the mass extinction, "studies that look at genomic comparisons of modern birds predict that the earliest divergence happened prior to that mass extinction," Torres said. "But their fossil record is extraordinarily scarce."

While the evidence pointing to V. iaai being associated with modern birds is strong, it's still not clear whether it really is a relative of modern ducks and geese, he said.

Daniel Ksepka, a paleontologist at the Bruce Museum in Connecticut who was not involved in the study, agreed. "Vegavis seems to have been a bit of an odd duck," he told Live Science in an email. "Provided the phylogeny is correct, a duck-like bill must have either evolved during the Cretaceous Period but been lost by Vegavis, or evolved multiple times independently. It will be interesting to see if future fossils confirm one of these scenarios."

V. iaai existed when global temperatures were far higher than they are today, and when Antarctica had a temperate climate and was covered in vegetation. Its distance from the asteroid impact may have provided the species with some protection from the devastation that followed.

For O' Connor, this study is the beginning of more discoveries to be found in the Cretaceous rocks of Antarctica. "The bird story is great, but we have other group[s] of animals, and, importantly, plants, that we can track through that mass extinction event that really let us get a better handle on ecosystem response to a global environmental perturbation," he said.

There are hundreds of thousands of meteorites hidden beneath Antarctica's icy surface, some of which are slowly sinking out of reach. You might think that these submerged space rocks would be very tricky, expensive and time-consuming to find. But in this excerpt from "The Meteorite Hunters" (Oneworld Publications, 2025), author Joshua Howgego reveals how researchers came up with a way to recover the lost objects — using just a lamp, a freezer and a block of ice.

As we know, meteorites can be split into three groups: stony, irons and stony-irons. If you look at the world collections of meteorites, the vast majority are stony meteorites; only 5.5% are either stony-iron or iron.

But here's the weird thing: If you look just at the meteorites recovered from Antarctica, only 0.7% are iron or stony-iron.

That's not just a small discrepancy. It means the chances of finding an iron-based meteorite are almost 10 times lower in Antarctica than they are anywhere else. And iron-containing meteorites are worth having, not least because they are useful for studying the way planets form their cores.

Earth has a molten iron core, the sloshing of which produces the magnetic field that protects our planet from harmful radiation in space (and produces the northern and southern lights). When planets began to form, though, the iron would have been distributed through their rocks and it would have gradually sunk into the middle of them as they grew larger.

It's thought that iron-containing meteorites might be fragments of planets that were part way through this core-forming process, but were smashed to pieces before they became big enough to endure.

Related: Never-before-seen shapes up to 1,300 feet long discovered beneath Antarctic ice

Anyway, learning about the missing irons planted a seed in Geoffrey Evatt's mind, and a while later he organised another of his workshops, this time at a countryside pub near Manchester, to talk about meteorites and ice. Several people came to give talks, including Katie Joy. She and Evatt had first met through some mutual friends on a rock-climbing holiday in Spain. She had recently moved to work at the University of Manchester too and, as an expert on meteorites who had already been out to Antarctica hunting the things, it was obvious that she should join the workshop.

It was at the pub workshop that Evatt and Joy began to discuss a delightfully simple solution to the problem of Antarctica's missing meteorites. Iron meteorites are typically dark or black in color and so absorb more warmth from sunlight than the lighter-coloured stony rocks. What if the iron stones were warming up to the point where they would actually melt the glacial ice beneath them and sink into it, perhaps even descending far enough so as to be hidden below the surface?

It was just a hypothesis, but it would explain a lot, and it was so simple that it had to be worth testing. Evatt worked out the mathematical model for how meteorites would absorb sunlight and the numbers seemed to check out. To test the idea, they would need some real meteorites, a block of ice, a freezer and a lamp.

That led them to Andrew Smedley, another University of Manchester researcher, who is an expert on sunlight and the way its particular wavelengths of light affect materials. Together with some students, Smedley, Evatt and Joy dreamed up an experiment.

They froze two roughly spherical and equally sized meteorites — one iron, one stony — in cubes of ice, specially prepared to contain no air bubbles, like real glacier ice. Then they stuck these in a huge walk-in freezer down the corridor from Smedley's office and shone a special lamp on the set-up to mimic the spectrum of light that comes from real sunlight.

They found that both meteorites sank. But the iron meteorite descended at 2.4 millimeters per hour, almost twice as quickly as the stony rock.

We know that in places where ice flow is impeded by mountain bedrock, meteorites buried in the ice are forced upwards. According to the calculations, this meant that as the iron meteorites get close to the surface of the ice and begin to absorb sunlight, they could plausibly begin to sink into the ice faster than the moving glacier could push them upwards. (The stony meteorites are subjected to that downward sinking drive too, but much less strongly, so that the upwelling pressure wins out and they are slowly thrust to the surface.)

The implication, the team thought, was that there could be a layer of iron meteorites hidden just beneath the surface of the ice sheets of Antarctica.

Extracted from "The Meteorite Hunters: On the Trail of Extraterrestrial Treasures and the Secrets Inside Them" by Joshua Howgego, published by Oneworld Publications.

The size of the Antarctic ice sheet can be hard to comprehend. Two kilometres thick on average and covering nearly twice the area of Australia, the ice sheet holds enough freshwater to raise global sea levels by 58 metres.

Ice loss from this sheet is projected to be the leading driver of sea level rise by 2100, yet its contribution remains highly uncertain. While sea levels are certain to rise this century, projections of the contribution from Antarctic ice vary from a 44 cm rise to a 22 cm fall.

Much of this uncertainty is because the ocean processes that control the fate of the sheet occur on an incredibly small scale and are very difficult to measure and model.

But recently scientists have made significant progress in understanding this "ice-ocean boundary layer." This progress is the subject of our new review paper, published today in Annual Reviews.

Shrinking, thinning and retreating

At the margins of the Antarctic ice sheet, glaciers flow into the Southern Ocean, forming floating ice shelves. These ice shelves act as keystones, stabilising the ice sheet. They're also shrinking.

The ocean melts ice shelves from below — a process known as "basal melting." Increased basal melting has led to the thinning and retreat of the ice sheet in some regions, raising global sea levels.

It has also slowed the deepest current in the global overturning circulation, a system of ocean currents that circulates water around the globe.

Like the glaciers that feed them, ice shelves are immense. Yet the ocean processes that control basal melting, and the fate of the entire Antarctic ice sheet, occur on the scale of millimetres. They happen in a thin layer of ocean, just beneath the ice.

The boundary layer between the ice shelf and the ocean is cold, miles from anywhere, and beneath very thick ice, so it’s no wonder it has hardly been measured at all.

Studying this layer with other techniques such as computer simulations is also a huge challenge. Until recently, the tiny motions within the ice-ocean boundary layer put accurate modeling of ice melt out of reach.

These twin challenges have long stymied efforts to answer the deceptively simple question: "How does the ocean melt Antarctic ice shelves?"

Modeling the micro-scale

Computer simulations of ocean processes aren't new.

But only recently have simulations of the ice-ocean boundary layer become feasible, as computing resources grow and the cost of using them shrinks.

Several research groups around the world have taken on this problem, modeling the micro-scale ocean flow that supplies heat to the ice for melting.

Researchers are looking for a relationship between what the ocean is doing, and how quickly the ice melts. So far, they've uncovered not just one relationship but several, each indicating a different melt "regime." Ocean conditions (temperature, salt content and the speed of ocean currents) and the shape of the ice determine which melting regime applies.

Ice sheet shape is key because meltwater is fresh and lighter than the surrounding ocean. Like hot air collecting at the top of a room, fresh, cold meltwater collects in hollows in the lower surface of the ice sheet, insulating the ice from the ocean water below and slowing melting.

For steeply sloping ice, the insulating effect is much less. The energetic flow of meltwater as it rises under steep ice leads to mixing with the warmer ocean waters. This increases melting.

Fast ocean currents have a similar effect, as they transfer heat to the ice.

Sonar-fitted robots

Recently, ocean robots, including autonomous underwater vehicles and tethered probes deployed by drilling through the ice, have provided unprecedented amounts of data on the environment beneath ice shelves.

Using sonar and cameras, these robots have revealed a weird and wonderful "icescape" on the underside of ice shelves.

This icescape is made of many different ice features, ranging from centimetres to kilometres in size. Some, like steep-sided crevasses, are formed by ice fracturing. Others, like dimpled depressions in the ice (often called "scallops"), stair-like "terraces", mussel-shaped "scoops", and larger basal channels, are thought to be formed by melt processes.

Our new knowledge of melting from computer simulations and robots sheds light on these features and how they form. The existence of melt regimes helps explain the evolution of steep-sided terraces, or why different features appear in distinct parts of an ice shelf.

For instance, in the warm, calm eastern part of the Dotson ice shelf in west Antarctica, an autonomous robot observed basal terraces. In the west of Dotson — which experiences cold, fast currents — large mussel-shaped scoops were discovered.

Uncertainties remain

Exactly how some of these features form is still unknown.

New simulations that allow the ice-water boundary to move in time show the "self-sculpting" behaviour of ice melt. This is similar to how dunes form and move in a desert.

However, new computer models are needed to simulate the formation and evolution of the whole icescape.

Some of the recent advances highlighted here are helping to reduce the uncertainty in our understanding of the contribution of the Antarctic ice sheet to global sea level rise.

However, incorporating our new understanding of basal melt, and the dynamic icescape it forms, into climate and ice sheet models still presents a huge challenge.

Overcoming this challenge is urgent. Accurate representation of melt in climate and ice sheet models will reduce the deep uncertainty in sea level rise projections, especially as ocean conditions — and ice shelf melt regimes — shift into the future.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Antarctica quiz

The world's largest iceberg — which is roughly the size of Rhode Island — is fast approaching a remote British Island and wildlife haven in the South Atlantic.

As of Jan. 16, the megaberg, known as A23a, is roughly 180 miles (290 kilometers) away from South Georgia and the South Sandwich Islands, according to location coordinates from the U.S. National Ice Center. A collision with these islands could be catastrophic for the large colonies of penguins, seals, and other wildlife that live there.

"Icebergs are inherently dangerous," Simon Wallace, a sea captain stationed on a government vessel in South Georgia, told BBC News. "I would be extraordinarily happy if it just completely missed us."

A23a, nicknamed the "queen of icebergs," measures 1,222 miles (1,967 kilometers) in surface area, according to the U.S. National Ice Center. It first broke off from Antarctica's Filchner Ice Shelf in 1986. However, it remained tethered to the seabed for more than 30 years before beginning its slow journey northwards in 2020, according to the British Antarctic Survey.

More recently, A23a got stuck again, spinning in one place just north of the South Orkney Islands. But, in December 2024 it finally broke free.

Related: Scientists peered into a secret Antarctic lake hidden beneath the ice — and uncovered a never-before-seen ecosystem

The movement of icebergs is always hard to predict because they are constantly changing, losing large chunks of ice from their sides and melting as they enter warmer waters. However, current forecasts suggest that A23a will be pushed by ocean currents to a stretch of water called the Drake Passage, often referred to as the place "where icebergs go to die."

South Georgia and the Sandwich Islands are located on the eastern edge of this passage, and are therefore no strangers to threats from oncoming icebergs.

"South Georgia sits in iceberg alley so impacts are to be expected for both fisheries and wildlife, and both have a great capacity to adapt," Mark Belchier, a marine ecologist who advises the South Georgia government, told the BBC.

However, these impacts can still sometimes be catastrophic for local wildlife. For example, in 2004, an enormous iceberg called A38 grounded on South Georgia's continental shelf, blocking feeding grounds for penguins and seals and leaving many of their chicks and pips dead on its beaches, the BBC reports.

A23a could break apart any day, with each fragment posing a potential risk to the island. These fragments may miss the islands altogether. But for now, Captain Wallace and his crew remain vigilant for any sign of the approaching behemoth. "We have searchlights on all night to try to see ice," he said. "It can come from nowhere."

"Warm" water is flowing toward one of Antarctica's biggest ice shelves, which, if it melted, could dramatically raise sea levels.

The Filchner-Ronne Ice Shelf (FRIS) extends over the Weddell Sea in Antarctica. Unlike some other Antarctic ice shelves, FRIS currently appears stable in our warming world. However, previous ocean modeling has shown that relatively warm water from the deep sea could threaten the integrity of this shelf.

In a study published Nov. 14, 2024 in the Journal of Geophysical Research: Oceans, researchers found that warm water flows more rapidly toward the shelf during warmer years, which could be linked to reduced sea ice cover during these periods, Eos magazine reported. If that is the case, then a dramatic decline in sea ice could cause the shelf to melt.

"If the warm water reaches underneath the ice shelf, it would melt the base of the ice shelf," study first author Nadine Steiger, a physical oceanographer at Sorbonne University in France, told Live Science in an email.

The melting of a massive ice shelf like FRIS would ultimately lead to huge sea level rise. However, researchers still have a lot to learn about this region, and it's unclear whether the increased flow of warm water is linked to climate change.

Kaitlin Naughten, an ocean-ice modeler at the British Antarctic Survey who was not involved in the study, told Live Science in an email that the warm water "may be a warning sign," but may also just be "normal variability" in the region. Either way, FRIS is unlikely to melt anytime soon.

"If worldwide governments fail to phase out fossil fuels and climate change spirals out of control, FRIS might have a big problem in a century or two," Naughten said.

Related: Earth from space: High winds paint puzzling ice streaks across the sea in Antarctica

FRIS is protected by thick ice and near-freezing seawater flowing over the underwater continental shelf that rings the coast of Antarctica in the Weddell Sea. However, in the summer, warmer water comes up onto the continental shelf from the open ocean and travels toward the ice shelf through a channel called the Filchner Trough, according to the study.

Naughten noted that the deep ocean water around Antarctica is about 33.8 degrees Fahrenheit (1 degree Celsius), so it's not actually particularly warm, but it's warmer than the freezing point of seawater, which is about 28.4 F (minus 2 C) — salt lowers the freezing point of water.

"You wouldn't want to go swimming there, but it can melt ice very quickly," Naughten said.

The amount of warm water flowing through the Filchner Trough and another previously unknown trough identified in the study was particularly high in 2017 and 2018 — and sea ice was also lower in those years. However, the study authors only had data from 2017 to 2021. Both Steiger and Naughten highlighted the importance of long-term observations to better understand the region and predict future ice shelf changes.

Ultimately, while scientists agree that warm water flooding the continental shelf would likely spell doom for FRIS, some research suggests that this would only happen in an extreme climate change scenario.

Naughten led a 2021 study published in the journal Nature that estimated the FRIS tipping point would only be crossed when global warming exceeded 12.6 F (7 C) above pre-industrial levels. That amount of warming is way above the already dangerous threshold of 2 C (3.6 F), which would greatly increase the chances of irreversible climate breakdown. For context, 2024 was the first year to breach 2.7 F (1.5 C).

"We need to monitor the Filchner-Ronne for signs of change, but other regions of Antarctica will melt away long before this one does," Naughten said. "We are already observing rapid ice loss in West Antarctica, which is the fastest-growing contribution to sea level rise."

Editor's Note: This story was updated on Wednesday, Jan. 22 at 1 p.m. EST to clarify that the freezing point of seawater is minus 2 C.