11.3 Europe and the Mediterranean

Assessments of projected climate change for Europe:

Annual mean temperatures in Europe are likely to increase more than the global mean. The warming in northern Europe is likely to be largest in winter and that in the Mediterranean area largest in summer. The lowest winter temperatures are likely to increase more than average winter temperature in northern Europe, and the highest summer temperatures are likely to increase more than average summer temperature in southern and central Europe.

Annual precipitation is very likely to increase in most of northern Europe and decrease in most of the Mediterranean area. In central Europe, precipitation is likely to increase in winter but decrease in summer. Extremes of daily precipitation are very likely to increase in northern Europe. The annual number of precipitation days is very likely to decrease in the Mediterranean area. The risk of summer drought is likely to increase in central Europe and in the Mediterranean area.

Confidence in future changes in windiness is relatively low, but it seems more likely than not that there will be an increase in average and extreme wind speeds in northern Europe.

The duration of the snow season is very likely to shorten in all of Europe, and snow depth is likely to decrease in at least most of Europe.

Although many features of the simulated climate change in Europe and the Mediterranean area are qualitatively consistent among models and qualitatively well understood in physical terms, substantial uncertainties remain. Simulated seasonal-mean temperature changes vary even at the sub-continental scale by a factor of two to three among the current generation of AOGCMs. Similarly, while agreeing on a large-scale increase in winter half-year precipitation in the northern parts of the area and a decrease in summer half-year precipitation in the southern parts of the area, models disagree on the magnitude and geographical details of precipitation change. These uncertainties reflect the sensitivity of the European climate change to the magnitude of the global warming and the changes in the atmospheric circulation and the Atlantic Meridional Overturning Circulation (MOC). Deficiencies in modelling the processes that regulate the local water and energy cycles in Europe also introduce uncertainty, for both the changes in mean conditions and extremes. Finally, the substantial natural variability of European climate is a major uncertainty, particularly for short-term climate projections in the area (e.g., Hulme et al., 1999).