A 695-billion-ton East Antarctica ice sheet gain, the largest recorded by the GRACE satellites that monitor the continent, has been traced to a warming pool of tropical ocean water that triggered a chain of atmospheric events between July 2021 and April 2023, according to a new study published in Nature on 19 August.
The research was led by the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS), according to Eco Magazine. Its conclusions challenge the prevailing assumption that occasional surges in Antarctic snowfall are primarily driven by the atmospheric moistening associated with CO2-induced global warming.
How the Tropical Warm Pool Drove East Antarctica Ice Sheet Gain
The mechanism begins in the tropical warm pool (TWP), the stretch of ocean where the tropical Pacific meets the Indian Ocean. Sustained warming there during the study period triggered a Rossby wave train directed toward East Antarctica’s Queen Mary Land and Wilkes Land. That wave train reorganised moisture transport across the region, allowing more atmospheric rivers to reach the continent.
Atmospheric rivers are long corridors of water vapour that travel vast distances through the atmosphere. When they reach cold regions such as Antarctica, that moisture falls as heavy snow. Water-vapour tracking simulations showed that, under the influence of what the researchers call a dipole circulation, moist air from the midlatitude Indian Ocean was carried into East Antarctica, producing persistent heavy snowfall over the Queen Mary Land and Wilkes Land region and temporarily reversing the continent’s long-term ice loss trend.
Atmospheric circulation model experiments confirmed that TWP warming was the direct driver of both the circulation changes and the snowfall response.
Context: Two Decades of Ice Loss
The scale of the gain stands out more sharply against the background trend. According to Energies Media, Antarctica had been losing an average of about 140.5 billion tons of ice per year over the previous two decades. The 695-billion-ton gain therefore represents roughly four years’ worth of that average annual loss, accumulated in less than two years.
That does not mean the continent is recovering. The study’s authors describe the episode as a temporary slowdown in a long-term decline, not a reversal of it. As warmer air drives both atmospheric moisture and poleward shifts in storm tracks, large but episodic snowfall events are expected to occur even as Antarctica continues to shed ice decade by decade. The question the study pursues is what actually caused this particular event.
The Role of Global Warming Remains Limited but Not Ruled Out
The study’s findings on the contribution of human-caused climate change are careful and qualified. The increase in regional snowfall attributable to anthropogenic influence was equivalent to only 9% of the observed snowfall anomaly, indicating that atmospheric moistening caused by global warming was not the primary driver.
Associate professor and study co-author Qinghua Ding addressed the question of whether the TWP warming was itself linked to global warming. ‘We found that this type of multiyear-TWP warming usually oscillates in the historical record,’ Ding said. ‘I believe it is not a CO2 favored pattern because global warming does not normally favor such fluctuations. However, we also cannot rule out the possibility.’
The study adds that similar sustained TWP-warming events occur approximately once every decade. If the pattern holds, a comparable teleconnection between the tropical warm pool and the East Antarctica ice sheet could emerge again around 2031 to 2033, a period worth watching given that the Antarctic Ice Sheet remains one of the principal sources of uncertainty in projections of future global sea-level rise.
The periodic nature of the phenomenon, and its apparent independence from CO2-driven forcing, is what gives the research its broader weight. Understanding the mechanism more precisely, and whether it interacts with long-term warming over time, is the open question the The Economic Times notes has now been placed squarely on the research agenda. The next potential TWP warming cycle will provide a live test of whether the findings hold.
