A research vessel was forced off course by a dangerous storm near Antarctica, and the crew found something no one expected—solid rock where shifting ice had once hidden the landscape. The discovery of a previously unknown island was not an isolated event but a direct result of the region’s rapid warming and retreating ice. It was a dramatic find, but it was only the most visible part of a much larger story unfolding beneath the frozen continent. Scientists using advanced radar and gravity tools are now seeing through kilometers of solid ice to uncover geological structures that have been hidden for millions of years.
Earlier this summer, a team of researchers published findings in the journal Nature Geoscience revealing a massive, fan-shaped network of basins and depressions buried beneath the East Antarctic ice sheet, with parts sitting under more than 3 kilometers of solid ice. Several features previously thought to be separate were actually linked as one single connected geological formation. Researchers believe the network was shaped by tectonic events tied to the formation and breakup of Gondwana, the ancient supercontinent that once included Antarctica, Africa, South America, Australia, and India. That breakup began roughly 180 million years ago, and the physical marks it left behind are now preserved beneath the ice.
The shape of the bedrock beneath an ice sheet is not just a matter of geological history. It plays a major role in controlling how ice moves, where it flows quickly, and where it stays anchored. The newly revealed basins give scientists a clearer picture of the hidden landscape beneath East Antarctica, helping refine the models used to predict how the ice sheet will respond as temperatures rise. Another study, focused on ice shelves in East Antarctica, found that channels carved into the undersides of these floating extensions of ice can trap warmer ocean water, dramatically increasing melting in specific areas.
Researchers in Norway found that melting inside these channels can increase by roughly tenfold in some places. The study focused on the Fimbul ice shelf in East Antarctica, a region generally considered colder and less vulnerable. The researchers found that even small inflows of warmer water could have a large effect when the ice base is shaped by channels, meaning some ice shelves considered stable may actually be more fragile than expected. As ice shelves thin and weaken, they lose their ability to hold back the glaciers behind them.
This can allow more land ice to flow into the ocean, potentially accelerating global sea level rise. The Intergovernmental Panel on Climate Change has identified weakening polar ice shelves as a major uncertainty in sea level predictions. Antarctica holds roughly 90% of Earth’s ice, and its ice shelves cover about 1. 5 million square kilometers.
While floating ice shelves do not directly raise sea levels when they melt, their instability can speed up the flow of land ice into the ocean. The continent’s most vulnerable regions contain enough ice to raise global sea levels by about 15 meters if it all melted. A new analysis led by Gton Frenzy of the Australian Antarctic Division combined computer modeling from nine research groups worldwide to estimate that Antarctic ice shelves have lost about 843 billion tons of ice per year in recent decades due to melting from underneath. That is roughly the amount of water that flows from the Nile River into the ocean each year.
The analysis, which took a decade to bring together, helped clarify one of the biggest uncertainties in projections of Antarctica’s ice sheet. Satellite data shows the continent lost about 93 billion tons of ice between 1992 and 2020 overall, though snowfall has increased across parts of the continent, complicating the picture. The coldest water in the ocean exists beneath Antarctic ice shelves, where pressure lowers the freezing point to about -2. 2°C.
It is extremely difficult to measure because satellites cannot see through the ice and ships cannot reach the cavities. Only a small number of holes have ever been drilled through ice shelves. One research team received an unexpected opportunity when an autonomous Argo float drifted beneath two ice shelves over 300 meters thick. The data showed that the Denman ice shelf was being exposed to warm water melting it from underneath.
The Denman glacier catchment contains enough ice to cause about 1. 5 meters of global sea level rise if it were completely lost. Scientists say glaciers in the distant geological past carved deep canyons into the Antarctic landscape as they expanded, essentially creating the conditions for their own collapse by giving warm water a path to move beneath the ice. The Antarctic ice sheet covers about 98% of the continent, stretching across roughly 14 million square kilometers with an average thickness of more than 2 kilometers.
It holds about 26. 5 million cubic kilometers of ice, accounting for roughly 61% of all fresh water on Earth. The West Antarctic ice sheet is classified as marine-based, with parts of its bed lying more than 2,500 meters below sea level. For years, scientists had very limited weather information from Antarctica, with fewer than 20 permanent weather stations across the continent.
Early data limitations led some studies in the early 2000s to report overall cooling outside the Antarctic Peninsula, and one 2002 analysis led by Peter Doran received widespread media attention. The findings were widely described as contradicting global warming, and the idea was later referenced in Michael Crichton’s 2004 novel State of Fear. In response, Doran published a statement in the New York Times explaining that his research had been misunderstood and used in ways that did not accurately represent what the study showed. The Antarctic Peninsula has warmed by about 3°C since the middle of the 20th century, about five times the global average.
Roughly 87% of the glaciers along the peninsula have retreated, along with the collapse of some of the largest floating ice shelves ever directly observed. Ice loss from Antarctica is now producing around 1,100 to 1,500 billion tons of fresh meltwater every year. As this meltwater flows into the Southern Ocean, it makes the seawater fresher and changes the way the ocean’s layers mix. This freshening is altering the major overturning circulation that moves water through the world’s oceans.
Since the 1970s, the upper part of the Southern Ocean circulation has strengthened by about 50 to 60%, while the lower part has weakened by roughly 10 to 20%. Natural climate patterns have also played a role, but scientists expect these changes to become more serious in the future. Under the worst climate change scenarios, the Southern Ocean circulation could lose about half its strength by 2050. Some researchers warn it could eventually collapse completely, which would be extremely difficult to reverse and would represent a major climate tipping point, similar to predictions about the Atlantic Meridional Overturning Circulation.
A collapse could take until near the year 2300 to fully develop, but the consequences could include major declines in fisheries, shifts in rainfall patterns across the Southern Hemisphere, and potential marine ecosystem collapse. These changes could develop over many decades or centuries, showing that what is happening in Antarctica today could influence ocean systems, weather patterns, and marine life far beyond the continent.
