Study: Warming in tropical pool slows Antarctic ice mass loss

A temporary reversal in the trend of Antarctic ice sheet mass loss from July 2021 to April 2023 has been linked to multi-year warming in the tropical warm pool region stretching across the western Pacific Ocean and eastern Indian Ocean.

This was revealed in a study conducted by researchers from China, the United States, Japan, Belgium and Hungary.

Data from satellites monitoring changes in Earth’s gravity show that the Antarctic Ice Sheet gained approximately 695 billion tonnes of mass during that period.

This development represents the largest mass gain since satellite records began in 2003.

According to the study, published online in the journal Nature on Wednesday (19/8), the phenomenon temporarily halted the long-term loss trend, which averaged around 140.5 billion tonnes per year between 2003 and 2024.

“The loss of Antarctic ice sheet mass has been a major contributor to global sea level rise in recent decades, increasing the risk of coastal flooding and exacerbating storm surge damage for coastal communities worldwide,” said Wang Yunhe, the study’s lead author and a researcher at the Institute of Oceanology, Chinese Academy of Sciences (CAS).

“However, scientists did not know why the ice sheet gained so much mass over a period of two to three years,” Wang continued.

The study found that around 68 per cent of the mass increase was concentrated in the Queen Mary Land–Wilkes Land region of East Antarctica.

The direct cause was persistent heavy snowfall in that region. However, the underlying climate trigger originated thousands of kilometres away.

The researchers traced the origins of the unusual snowfall to sustained warming in the tropical warm pool, a vast expanse of warm water stretching across the western Pacific Ocean and eastern Indian Ocean that contains some of the warmest seawater on Earth.

From 2021 to 2023, the warming triggered large-scale atmospheric waves that travelled thousands of kilometres towards Antarctica.

There, the waves altered wind patterns and steered moist air from the mid-latitude Indian Ocean towards Queen Mary Land–Wilkes Land.

The result was persistent heavy snowfall, which significantly added ice mass to the ice sheet.

“However, this temporary slowdown does not reverse the long-term trend of Antarctic ice sheet mass loss, and West Antarctica remains the primary region continuing to experience mass loss,” said Wang.

“Understanding how Antarctic ice mass changes helps scientists project sea level rise more accurately. More reliable projections can help coastal communities prepare for increasingly frequent flooding and more severe storm surge damage to homes, roads and other infrastructure,” he said.

“Such planning needs to account for both long-term sea level rise and short-term natural climate fluctuations,” Wang added.