Heterogeneous Warming Rates and Decline in Snow Persistence across Mountains Worldwide

Abstract

The warming of mountainous regions has become evident in recent years with a global average warming rate of 1.41 °C from 1979 to 2022. Our study aims to understand observed changes in snow persistence across mountain regions worldwide, using reanalysis and satellite data. By taking a global perspective, we bridge the gap between regional findings and provide a comprehensive understanding of the impact of increases in global warming on mountain snow decline. Here, we demonstrate that the mountain snow persistence is significantly declining over the past 44 years, with a global mean decline of 7.67 %. The trends in regional snow cover persistence exhibit a heterogeneous and non-linear response to its regional warming rate. A decomposition of snow depth reveals the snowfall ratio majorly contributes to high latitudes, and the snowfall accumulation ratio plays a large role where the melting trend exceeds the snowfall trend. The recent Coupled Model Intercomparison Project 6 (CMIP6) has shown limitations in accurately capturing the mountain snow persistence. Our study provides valuable insights into the intricate interplay between global warming and declining snow cover persistence. Our findings attribute the observed reduction in snow persistence and shed light on decreased snowfall with increased snow melting contributions. Disclosure of the impact of this changing mountain snow is critical for informing sustainable development and preparing for the potential consequences of these changes.