Vanishing of the El Niño-induced delay effect on the ice mass loss of West Antarctica in future climate change

Abstract

The strong El Niño has delayed the ice mass loss of West Antarctica under global warming by inducing weakening of the Amundsen Sea Low (ASL) and consequent extreme snowfall. However, it is not yet clear whether the mechanism will continue in the future warmer climate. Analysis of future climate scenarios from the CMIP6 models shows that the El Niño-induced increases in snowfall over West Antarctica will disappear with intensifying global warming. In the high-emissions scenario (SSP5-8.5), precipitation anomaly owing to El Niño turns to negative from the 2050s, and from the 2060s in the SSP3-7.0, and consequently the El Niño-induced mass loss delay effect vanishes. This is because the stronger polar jet related with positive SAM trend would shift the ASL anomaly toward the east and the equator in the warmer climate, which would prevent water vapor transport into the interior of West Antarctica.