Compound coldwave and freezing-snow events decrease during 1994–2023 over global land area

With accelerating global warming, compound climate extremes pose amplified threats to ecosystems and socio-economic stability. However, the occurrence and evolution of Compound Coldwave and Freezing-Snow (CCFS) events in a warming climate remain a critical knowledge gap. This study provides a quantitative assessment of the spatiotemporal changes of CCFS characteristics, including its frequency, duration, and severity from 1964 to 2023, by integrating daily minimum temperature data from Berkeley Earth with hourly precipitation amount and precipitation type data from the ERA5 reanalysis. The spatial distribution of CCFS events exhibits a pronounced interhemispheric asymmetry, with over 90% of occurrences located in the Northern Hemisphere. Mid- to high-latitude regions of Eurasia and North America, where show the highest CCFS frequency, also experienced substantial temporal changes. Compared to the earlier period (1964−1993), notable declines in CCFS frequency, total duration, deficit heat, and combined severity are observed across most land regions during the recent warming period (1994−2023). Globally averaged trends reveal a faster reduction in CCFS frequency and total duration, as opposed to a slower decline in deficit heat and combined severity. The reduction has been particularly rapid in the top 20% most affected land areas, concentrated in subtropical North America, northern/eastern Europe, and Siberia. In these regions, average event frequency, duration, deficit heat, and combined severity declined markedly from approximately 3.5 events, 28 d, −44 °C, and 25 in 1964 to about 2 events, 18 d, −14 °C, and 17 in 2023. However, the average duration per event extends from 1964 to 2023, especially across mid to high latitudes of the Northern Hemisphere. Furthermore, CCFS frequency and duration demonstrate a nearly linear decrease with global warming, while severity indicators follow a nonlinear, logarithmic decay. This disparity indicates distinct sensitivities among different CCFS characteristics. For all CCFS indicators except average duration, the linear component of the response outweighs the nonlinear component. The results will aid forecasting efforts and help to improve hazard preparedness and mitigation strategies.