A new study published in Nature Communications reveals that summer warming deep inside East Antarctica is being driven by rapid ocean warming thousands of kilometers away in the southern Indian Ocean. The findings further challenge long-standing assumptions that the vast East Antarctic Ice Sheet (EAIS), which holds nearly two-thirds of the world’s freshwater ice, is relatively insulated from global climate change.

The world is experiencing rising temperatures due to human-induced global warming, but until now, there have been relatively few studies documenting the impact of this warming on the EAIS. Historically, East Antarctica’s climate variability has been strongly tied to the Southern Annular Mode (SAM), a large-scale atmospheric pattern that influences westerly winds over the Southern Ocean. In its positive phase, SAM strengthens these winds and reduces the north–south flow of warm air, leading to cooler conditions over East Antarctica. Throughout much of the late 20th century, this persistent positive SAM trend effectively masked the influence of anthropogenic warming, causing the EAIS to be regarded as less vulnerable than other parts of the continent.

 However, despite the continued influence of SAM, recent decades have told a different story. Since the early 1990s, scientists have observed widespread warming over the EAIS, particularly during austral spring (September–November) and summer (December–February). This paradox suggests that changes in atmospheric circulation, probably linked to global climate change, may be altering the way SAM interacts with the Antarctic climate. Instead of protecting East Antarctica, the shifting patterns appear to be making the region more susceptible to warming than previously understood.

Studying these changes has been difficult, as most Antarctic research stations are located along the coast, with only two long-term sites—Amundsen-Scott and Vostok—situated in the interior. To better understand the region’s climate trends, researchers reconstructed a continuous 30-year temperature record from three remote inland stations—Mizuho, Relay Station, and Dome Fuji. Data from these sites have historically been limited and fragmented due to extreme conditions and the logistical challenges of maintaining long-term measurements. The team addressed these gaps by combining automatic weather station records with bias-corrected reanalysis data from the ERA5, a global climate dataset from the European Centre for Medium-Range Weather Forecasts that blends observations with a modern forecasting model. Rigorous quality checks were applied to account for potential errors such as sensor biases and snow accumulation effects. This effort produced the most complete and reliable temperature dataset to date for the interior of eastern Dronning Maud Land.

The results showed statistically significant warming at all three inland stations between 1993 and 2022, with the most rapid increases occurring from October through March, the austral spring and summer seasons. Warming during this half-year period was particularly striking, with some sites experiencing temperature rises of nearly 0.9°C per decade—nearly double the annual average trend. Importantly, these changes were not observed to the same degree at nearby coastal stations, underscoring that the warming signal originates within the continent’s interior.

The study was led by Naoyuki Kurita of Nagoya University in Japan with prominent contributions by  David Bromwich, Research Professor in the Atmospheric Sciences Program of the Department of Geography and Senior Research Scientist with the Byrd Polar and Climate Research Center at The Ohio State University.

Researchers connected the inland warming patterns to large-scale atmospheric circulation and ocean–atmosphere interactions. They traced this warming to rapid sea surface temperature increases in the southern Indian Ocean, where the Subtropical Frontal Zone (STFZ), a sharp boundary between warm and cool waters, has intensified by about 20% over the past three decades, primarily due to global climate change. This enhanced ocean gradient has fueled atmospheric circulation patterns that transport warmer air masses southward into East Antarctica’s interior. The mechanism creates a “meridional dipole” response in the atmosphere, where opposing north–south shifts in circulation funnel heat directly into the heart of the EAIS.

This discovery carries significant implications for global climate science. For decades, East Antarctica has been viewed as less sensitive to human-driven warming, in part because of the influence of the Southern Annular Mode, which usually suppresses warm air intrusions. However, the new research shows that ocean-driven atmospheric shifts can override these protective effects, exposing even the coldest and most remote parts of Antarctica to rapid climate change.

 If the warming trend continues and extends to the coastal regions, it could destabilize the EAIS, which contains enough ice to raise global sea levels by more than 50 meters. Even modest changes in surface temperature could influence ice dynamics, snow accumulation, and meltwater processes. As the authors emphasize, the climate of Antarctica’s interior is more vulnerable to distant ocean changes than previously thought, underscoring the interconnectedness of Earth’s climate system.

Read more about the study.