The East Antarctic Ice Sheet has long been considered a bastion of stability in the global climate system, a frozen interior so vast and isolated that it was thought largely shielded from the rising heat affecting the rest of the planet. For decades scientists believed that the continent’s unique atmospheric patterns, dominated by the Southern Annular Mode, had kept the worst of human-induced warming at bay. That assumption has now been overturned by new research showing that the deep interior of East Antarctica is warming at a pace that should alarm the world.
The new study, led by Naoyuki Kurita of Nagoya University and published in Nature Communications in September 2025, draws on a painstaking reconstruction of three decades of inland temperature records from Dome Fuji, Relay Station, and Mizuho. These are among the few weather monitoring points in the heart of East Antarctica, where harsh conditions and sparse observational coverage have historically left gaping holes in climate data. The team filled those gaps using bias-corrected reanalysis from the European Centre for Medium-Range Weather Forecasts, producing the most complete record yet of East Antarctic surface air temperature from 1993 to 2022.
The results are stark. At all three inland stations, the researchers found statistically significant warming trends in annual mean temperature. More troubling is the fact that the strongest signal is concentrated in the warm half of the year, from October through March. During this period, average warming has been measured at nearly 0.9 degrees Celsius per decade in some locations. In practical terms, that means parts of the interior of East Antarctica are now warming twice as fast during summer months as their own annual average suggests. This is not a localized anomaly. The records correlate strongly with temperature data from other plateau stations such as Vostok and Amundsen-Scott, confirming that the warming is widespread across the East Antarctic interior.
For decades, modest cooling or muted warming in East Antarctica was explained by the Southern Annular Mode. In its positive phase, this mode strengthens the westerly winds that circle the continent, reducing the flow of warmer air from lower latitudes. That dynamic led many to conclude that the East Antarctic Ice Sheet was less vulnerable than its western counterpart. Yet the past two decades have revealed a very different story. Despite the persistence of a generally positive Southern Annular Mode, the East Antarctic interior has experienced marked and accelerating warming. The new research explains why: the Southern Annular Mode’s influence has been modified by ocean-driven circulation patterns originating far to the north.
The trigger lies in the southern Indian Ocean. Since the 1990s, sea surface temperatures there have risen sharply, with the basin-scale warming intensified by the negative phase of the Interdecadal Pacific Oscillation and by excess heat absorbed during the so-called global warming hiatus of the early 2000s. The effect has been to strengthen the Subtropical Frontal Zone, a powerful band of contrasting sea surface temperatures that separates warm subtropical waters from cooler mid-latitude waters. Over the past thirty years this gradient has steepened by roughly 20 percent. Such a shift has profound atmospheric consequences.
A strengthened Subtropical Frontal Zone amplifies storm track activity and reshapes upper-level atmospheric flows, producing what scientists call a meridional dipole pattern. The outcome is an increase in northerly winds that push warm air deep into East Antarctica’s interior. In essence, the Indian Ocean is telegraphing its excess heat directly into the frozen heart of the continent. The records from Dome Fuji and Relay Station capture this signal unmistakably. The warming is not being driven by local changes within Antarctica but by remote oceanic forcing, a reminder that the Earth’s climate is an interconnected system where disturbances in one region reverberate across thousands of miles.
The researchers note that the correlation between strengthened Subtropical Frontal Zone gradients and interior Antarctic warming is robust. At Relay Station, the variability of warm half-year temperatures is strongly tied to these oceanic shifts, with a correlation coefficient of 0.76, statistically significant at the 95 percent confidence level. In plain terms, when the southern Indian Ocean’s temperature gradient sharpens, the East Antarctic interior heats up. This relationship has persisted throughout the three-decade record, leaving little doubt about the causal link.
Another element highlighted in the study is the weakening of barriers that once masked the true impact of warming. Along the coast, steep ice topography and persistent sea ice cover have historically deflected or moderated the arrival of warm air masses. Barrier jets, formed when northerly winds slam into the wall of the ice sheet and are forced eastward, have shielded coastal stations from experiencing the same degree of warming as the interior. Extensive sea ice has further limited the transfer of ocean heat to the atmosphere. But these buffers are breaking down. Antarctic sea ice has declined precipitously since 2016, hitting record lows in 2023. As that protective layer diminishes, coastal stations may soon begin to register the same warming trend now visible inland.
The implications are profound. The East Antarctic Ice Sheet contains the overwhelming majority of Earth’s freshwater ice. Unlike West Antarctica, where glaciers and ice shelves have already shown signs of irreversible retreat, East Antarctica was long believed to be more resilient. That confidence was based on the perception of stable interior conditions. The discovery that even the plateau at Dome Fuji is experiencing warming approaching one degree per decade during summer shatters that belief. With warming concentrated in the months of maximum solar radiation, the risk of surface melting episodes rises sharply. Such events have already been observed in extraordinary cases, including the East Antarctic heat wave of March 2022. The new data suggests they may become more frequent as summer warming accelerates.
The mechanics of this warming are not simply natural variability. The researchers emphasize that while multi-decadal cycles like the Interdecadal Pacific Oscillation and the Indian Ocean Subtropical Dipole have played a role, the root driver is the accumulation of anthropogenic heat in the oceans. During the early 21st century, excess heat from greenhouse gas emissions was absorbed disproportionately by the Pacific and Indian Oceans. That energy is now manifesting in intensified sea surface temperature gradients, altered atmospheric circulation, and rising Antarctic temperatures. In other words, the fingerprints of human activity are etched into the very heart of the coldest continent on Earth.
The study also underscores the inadequacy of sparse observational networks in Antarctica. Prior to this reconstruction, only Vostok and Amundsen-Scott had long-term interior temperature records, leaving much of the East Antarctic plateau a blank spot in climate monitoring. By carefully correcting biases in automated weather stations, addressing issues such as snow accumulation and radiation shield errors, and supplementing missing data with corrected reanalysis, the authors have provided the first clear multi-decadal record for this region. The picture it paints is one of steady and accelerating warming, particularly during the period when the ice sheet is most vulnerable to surface melt.
While inland warming has so far been most pronounced, the coastal picture cannot be ignored. As sea ice continues to thin and retreat, and as barrier jets weaken, the coastal East Antarctic may begin to reflect the same signals. Basal melting of ice shelves already contributes significantly to sea level rise. If surface meltwater begins to spread across East Antarctic ice shelves, the risk of structural collapse increases, raising the possibility of rapid contributions to global sea levels. Such a scenario would have consequences measured not in centimeters but in meters over the long term.
Perhaps most alarming is the rate of change. A warming pace of nearly one degree per decade is rapid by any standard, but in the context of East Antarctica it is unprecedented. For a region long thought insulated from the effects of climate change, the revelation that it is warming faster in summer than most of the globe should force a reassessment of global climate projections. If the East Antarctic Ice Sheet is more sensitive than previously recognized, then current sea level rise estimates may be underplaying the long-term risks.
The findings also highlight the global interconnection of climate systems. A change in Pacific trade winds alters the Indonesian Throughflow, which warms the Indian Ocean, which in turn sharpens temperature fronts, which then drive warm air into Antarctica. The chain stretches across thousands of kilometers, demonstrating how no region of the Earth is truly isolated. Local stability cannot be assumed in a world where oceans, atmosphere, and ice sheets are bound together by such feedbacks.
The authors call for expanded monitoring, not only of inland Antarctic stations but also of the southern Indian Ocean, where the key drivers of this process are unfolding. Without comprehensive data, models will continue to underestimate the vulnerability of East Antarctica. Already the study shows that what was once considered a stable ice reserve is responding rapidly to remote forcing. The conclusion is unavoidable: the East Antarctic Ice Sheet is not immune. It is being reshaped by global warming in real time.
The consequences of these changes will not be confined to Antarctica. With billions of people living in coastal regions worldwide, even modest additional contributions to sea level rise from East Antarctica could displace populations, inundate infrastructure, and alter coastlines. The world’s largest store of frozen water is revealing cracks in its armor, and the trigger lies far from its shores in the warming waters of the Indian Ocean. What was once seen as a distant and improbable threat is now a measurable reality unfolding across the frozen continent’s vast interior.
Source:
Kurita, N., Bromwich, D.H., Kameda, T., Motoyama, H., Hirasawa, N., Mikolajczyk, D.E., Keller, L.M. & Lazzara, M.A. (2025). Summer warming in the East Antarctic interior triggered by southern Indian Ocean warming. Nature Communications, 16:6764. https://doi.org/10.1038/s41467-025-61919-3
