Effects of a Warming Climate on Daily Snowfall Events in the Northern Hemisphere

Using simulations performed with 24 coupled atmosphere-ocean global climate models from phase 5 of the Coupled Model Intercomparison Project (CMIP5), projections of Northern Hemisphere daily snowfall events under the RCP8.5 emissions scenario are analyzed for the periods 2021-2050 and 2071-2100 and compared to the historical period of 1971-2000. The overall frequency of daily snowfall events is simulated to decrease across much of the Northern Hemisphere during the 21st century, except at the highest latitudes such as far northern Canada, northern Siberia, and Greenland. Seasonal redistributions of daily snowfall event frequency and average daily snowfall are also projected to occur in some regions. For example, large portions of the Northern Hemisphere, including much of eastern Canada, northern Siberia, Tibet, and Greenland, are projected to experience increases in average daily snowfall and event frequency in midwinter. But in warmer months, the regions with increased snowfall become fewer in number and are limited to northeastern Canada, northern Siberia, and Greenland. These simulations also show changes in the frequency distribution of daily snowfall event intensity, including an increase in heavier snowfall events even in some regions where the overall snowfall decreases. The projected changes in daily snowfall event frequency exhibit some dependence on the temperature biases of the individual models in certain regions and times of the year, with colder models typically on the higher end of the event frequency changes and warmer models on the lower end, particularly in the colder regions during the midwinter months where the largest model biases tend to occur.