Abstract
Intense surface melt and subsequent meltwater ponding are the key triggers for the disintegration of ice shelves in the Antarctic Peninsula (AP). Although a long-term decline in AP surface melt has been evident since the early 1990s, episodes of intense surface melt events have frequently been reported in recent years. Here, using 1979-2023 daily surface melt rates from regional climate models, we show that this declining trend has reversed, with November-February surface melt increasing significantly by 3% year-1 (p < 0.05) between 2009 and 2022. Decomposition of trends based on circulation classification indicates that changes in the frequency of atmospheric circulation patterns cannot account for this enhancement. Instead, the thermodynamics-linked to variations in the surface energy budget independent of atmospheric circulation contribute 80% of the positive trend in AP surface melt. Analysis of extreme surface melt events further supports the dominant thermodynamic contribution.