Extremes of Temperature and Precipitation

Very little work has been done in analysing future changes in extreme events in the Arctic. However, the MMD simulations indicate that the increase in mean temperature and precipitation will be combined with an increase in the frequency of very warm and wet winters and summers. Using the definition of extreme season in Section 11.1.2, every DJF and JJA season, in all model projections, is ‘extremely’ warm in the period 2080 to 2099 (Table 11.1). The corresponding numbers for extremely wet seasons are 90 and 85% for DJF and JJA. For the other scenarios, the frequency of extremes is very similar, except that for the wet seasons under B1, which is smaller (~63%).

Cryosphere

Northern Hemisphere sea ice, snow and permafrost projections are discussed in Section 10.3; projected changes in the surface mass balance of arctic glaciers and of the Greenland Ice Sheet are discussed in Sections 10.3 and 10.7.