Contrasting trends of extreme rainfall and snowfall in the Northern Hemisphere

Abstract

Global warming has modified the distribution between solid and liquid precipitation, leading to changes in the intensity and frequency of extreme rainfall and snowfall. However, the distinct response mechanisms of these extremes to warming remain underexplored at the global scale, particularly in regard to the drivers behind their contrasting trends. To address this gap, we conducted a hemispheric-scale analysis using the ERA5-Land reanalysis dataset (1950–2022) and quantified phase-specific intensification patterns across the Northern Hemisphere. According to the results, extreme rainfall is accelerating at a rate nine times higher (0.269 mm per year, p < 0.05) than that of extreme snowfall (0.029 mm per year, p > 0.05), as identified by the 90th percentile method, which highlights the differing thermal sensitivities of liquid and solid precipitation. This contrast becomes further evident in their temperature responses: extreme rainfall displays a marked increase with warming (2.27 mm/K), whereas extreme snowfall decreases (−1.63 mm/K), especially across mid-latitudes (30°–60°N). Notably, both types of extremes show increasing contributions to total precipitation (rainfall: +0.038% per year, p < 0.05; snowfall: +0.017% per year, p < 0.05), which indicates systemic shifts in precipitation regimes. Mechanistic analysis identified baseline snowfall magnitude and its temporal trend as dominant factors governing phase-specific intensification, with its spatial variability shaped by latitude, elevation and large-scale circulation patterns. This study offers novel insights into extreme precipitation dynamics from a phase-specific perspective.