Vanishing the El Niño-induced delayed ice mass loss of West Antarctica in future climate

The strong El Niño causes a weakening of the Amundsen Sea Low and consequent extreme snowfall event in West Antarctica through atmospheric teleconnection, thereby delaying the ice mass loss of West Antarctica due to global warming and the resulting sea level rise in the short term. However, it is not yet clear whether this mechanism will continue in future climate. In this study, analysis of future scenarios from the CMIP6 ESMs shows that El Niño-induced increases in snowfall over West Antarctica will disappear in the future with ongoing global warming. In the high emission scenario (SSP5-8.5), the precipitation anomaly due to El Niño turns to negative from the 2030s, and from the 2040s in the SSP3-7.0, and it denotes that the El Niño-induced delayed effect vanishes. This change occurs because the Amundsen Sea low anomaly induced by El Niño migrates equator-eastward as warming progresses, preventing the water vapor at low latitude from advecting to the interior of West Antarctica. It is also shown that stronger polar jets related with positive SAM trend would shift the Amundsen Sea Low anomaly toward the equator in the warmer climate. Finally, the occurrence of extreme snowfall event due to strong El Niño will also disappear in future climate, and as a result, it is predicted that the internal resilience of atmospheric variability against the ice mass loss of West Antarctica will be lost. On the other hand, if carbon neutrality is achieved and the global warming until 2100 is kept below 2°C, the atmospheric resilience to compensate for ice mass loss is expected to continue.