News release

From: Springer Nature

Climate: Slowing of Antarctic ice sheet mass loss likely temporary

A temporary slowing in the rate of Antarctic ice sheet mass loss in 2021–2023 may be explained by sea temperature rises thousands of miles away in the subtropical ocean causing increased snowfall in the eastern Antarctic, according to research published in Nature. This event is thought to occur approximately once a decade, meaning that the pause in total sheet ice loss is likely temporary and distinct from the effects of global warming.

Changes in the mass of Antarctic ice sheets can be influenced by numerous factors, including climatic events thousands of miles away. Between 2021 and 2023, East Antarctica experienced an increase in ice sheet mass that outweighed losses in West Antarctica, leading to a slowdown in the rate of total ice sheet mass loss. Although previous studies have attempted to rationalize this observation, none has been conclusive.

Qinghua Ding and colleagues use data from both observational and model experiments to propose a new mechanism for this anomaly. They link the mass-gain event to surface temperature anomalies in the tropical warm pool, a region of ocean between the western Pacific and eastern Indian Ocean in which surface temperatures regularly exceed 28°C. This area was shown to have experienced unusually persistent warming between 2021 and 2023 in comparison to the previous two decades.

The authors posit that this warming induces a phenomenon called a Rossby-wave train (a series of alternating high- and low-pressure weather patterns). This process eventually leads to the formation of a high-pressure anomaly over East Antarctica, resulting in increased precipitation and driving ice sheet mass gain. Analysis of ice cores from the East Antarctic region suggest that this climate event, connecting changes in climate between two distant locations, may occur approximately once every ten years, meaning that any ice sheet mass gain is likely to be temporary.

Jonathan Wille, author of an accompanying News & Views article, stresses that “variability in the tropical climate must also be taken into account to understand the future of Antarctica and the rest of the planet”.