For the first time, wide-ranging impacts of changes in current climate have been documented in Europe (very high confidence).
The warming trend and spatially variable changes in rainfall have affected composition and functioning of the cryosphere (retreat of glaciers and extent of permafrost) as well as natural and managed ecosystems (lengthening of growing season, shift of species and human health due to a heatwave of unprecedented magnitude) [12.2.1]. The European heatwave in 2003 (see Figure TS.13) had major impacts on biophysical systems and society (around 35,000 excess deaths were recorded) [12.6.1]. The observed changes are consistent with projections of impacts due to future climate change [12.4].
Climate-related hazards will mostly increase, although changes will vary geographically (very high confidence).
By the 2020s, increases are likely in winter floods in maritime regions and flash floods throughout Europe [12.4.1]. Coastal flooding related to increasing storminess (particularly in the north-east Atlantic) and sea-level rise are likely to threaten an additional Errata 1.5 million people annually by the 2080s; coastal erosion is projected to increase [12.4.2]. Warmer, drier conditions will lead to more frequent and prolonged droughts (by the 2070s, today’s 100-year droughts will return every 50 years or less in southern and south-eastern Europe), as well as a longer fire-season and increased fire risk, particularly in the Mediterranean region [12.3.1, 12.4.4]. A higher frequency of catastrophic fires is also expected on drained peatlands in central and eastern Europe [12.4.5]. The frequency of rockfalls will increase due to destabilization of mountain walls by rising temperatures and melting of permafrost [12.4.3].
Some impacts may be positive, such as reduced cold-related mortality because of increasing winter temperatures. However, on balance, without adaptive measures, health risks due to more frequent heatwaves, especially in southern, central and eastern Europe, flooding and greater exposure to vector- and food-borne diseases are anticipated to increase [12.4.11].
Climate change is likely to magnify regional differences in Europe’s natural resources and assets (very high confidence).
Climate-change scenarios indicate significant warming (A2: 2.5 to 5.5°C; B2: 1 to 4°C), greater in winter in the north and in summer in south and central Europe [12.3.1]. Mean annual precipitation is projected to increase in the north and decrease in the south. Seasonal changes, however, will be more pronounced: summer precipitation is projected to decrease by up to 30 to 45% over the Mediterranean Basin, and also over eastern and central Europe and, to a lesser degree, over northern Europe even as far north as central Scandinavia [12.3.1]. Recruitment and production of marine fisheries in the North Atlantic are likely to increase [12.4.7]. Crop suitability is likely to change throughout Europe, and crop productivity (all other factors remaining unchanged) is likely to increase in northern Europe, and decrease along the Mediterranean and in south-east Europe [12.4.7]. Forests are projected to expand in the north and retreat in the south [12.4.4]. Forest productivity and total biomass are likely to increase in the north and decrease in central and eastern Europe, while tree mortality is likely to accelerate in the south [12.4.4]. Differences in water availability between regions are anticipated to become more pronounced: annual average runoff increasing in north/north-west, and decreasing in south/south-east Europe (summer low flow is projected to decrease by up to 50% in central Europe and by up to 80% in some rivers in southern Europe) [12.4.1, 12.4.5].
Figure TS.13. Characteristics of the summer 2003 heatwave: (a) JJA temperature anomaly with respect to 1961-1990; (b-d) June, July, August temperatures for Switzerland; (b) observed during 1864-2003; (c) simulated using a regional climate model for the period 1961-1990; (d) simulated for 2071-2100 under the SRES A2 scenario. The vertical bars in panels (b-d) represent mean summer surface temperature for each year of the time period considered; the fitted Gaussian distribution is indicated in black. Reprinted by permission from Macmillan Publishers Ltd. [Nature] (Schär et al., 2004), copyright 2004, [F12.4].
Water stress is likely to increase, as well as the number of people living in river basins under high water stress (high confidence).
Water stress is likely to increase over central and southern Europe. The percentage of area under high water stress is likely to increase from 19% to 35% by the 2070s, Errata and the number of people at risk from 16 to 44 million [12.4.1]. The regions most at risk are southern Europe and some parts of central and eastern Europe [12.4.1]. The hydropower potential of Europe is expected to decline on average by 6%, and by 20 to 50% around the Mediterranean by the 2070s [184.108.40.206].
It is anticipated that Europe’s natural systems and biodiversity will be substantially affected by climate change (very high confidence). The great majority of organisms and ecosystems are likely to have difficulty in adapting to climate change (high confidence).
Sea-level rise is likely to cause an inland migration of beaches and loss of up to 20% of coastal wetlands [12.4.2.], reducing the habitat availability for several species that breed or forage in low-lying coastal areas [12.4.6]. Small glaciers will disappear and larger glaciers substantially shrink (projected volume reductions of between 30% and 70% by 2050) during the 21st century [12.4.3]. Many permafrost areas in the Arctic are projected to disappear [12.4.5.]. In the Mediterranean, many ephemeral aquatic ecosystems are projected to disappear, and permanent ones shrink and become ephemeral [12.4.5]. The northward expansion of forests is projected to reduce current tundra areas under some scenarios [12.4.4]. Mountain communities face up to a 60% loss of species under high-emissions scenarios by 2080 [12.4.3]. A large percentage of the European flora (one study found up to 50%) is likely to become vulnerable, endangered or committed to extinction by the end of this century [12.4.6]. Options for adaptation are likely to be limited for many organisms and ecosystems. For example, limited dispersal is very likely to reduce the range of most reptiles and amphibians [12.4.6]. Low-lying, geologically subsiding coasts are likely to be unable to adapt to sea-level rise [12.5.2]. There are no obvious climate adaptation options for either tundra or alpine vegetation [12.5.3]. The adaptive capacity of ecosystems can be enhanced by reducing human stresses [12.5.3, 12.5.5]. New sites for conservation may be needed because climate change is very likely to alter conditions of suitability for many species in current sites (with climate change, to meet conservation goals, the current reserve area in the EU would have to be increased by 41%) [12.5.6].
Nearly all European regions are anticipated to be negatively affected by some future impacts of climate change and these will pose challenges to many economic sectors (very high confidence).
In southern Europe, climate change is projected to worsen conditions (high temperatures and drought) in a region already vulnerable to climate variability. In northern Europe, climate change is initially projected to bring mixed effects, including some benefits, but as climate change continues, its negative effects are likely to outweigh its benefits [12.4].
Agriculture will have to cope with increasing water demand for irrigation in southern Europe due to climate change (e.g., increased water demand of 2 to 4% for maize cultivation and 6 to 10% for potatoes by 2050), and additional restrictions due to increases in crop-related nitrate leaching [12.5.7]. Winter heating demands are expected to decrease and summer cooling demands to increase due to climate change: around the Mediterranean, 2 to 3 fewer weeks in a year will require heating but an additional 2 to 5 weeks will need cooling by 2050 [12.4.8]. Peak electricity demand is likely to shift in some locations from winter to summer [12.4.8]. Tourism along the Mediterranean is likely to decrease in summer and increase in spring and autumn. Winter tourism in mountain regions is anticipated to face reduced snow cover (the duration of snow cover is expected to decrease by several weeks for each °C of temperature increase in the Alps region) [12.4.9, 12.4.11].
Adaptation to climate change is likely to benefit from experiences gained in reactions to extreme climate events, by specifically implementing proactive climate-change risk management adaptation plans (very high confidence).
Since the TAR, governments have greatly increased the number of actions for coping with extreme climate events. Current thinking about adaptation to extreme climate events has moved away from reactive disaster relief and towards more proactive risk management. A prominent example is the implementation in several countries of early-warning systems for heatwaves (Portugal, Spain, France, UK, Italy, Hungary) [12.6.1]. Other actions have addressed long-term climate change. For example, national action plans have been developed for adapting to climate change [12.5] and more specific plans have been incorporated into European and national policies for agriculture, energy, forestry, transport and other sectors [12.2.3,12.5.2]. Research has also provided new insights into adaptation policies (e.g., studies have shown that crops that become less economically viable under climate change can be profitably replaced by bioenergy crops) [12.5.7].
Although the effectiveness and feasibility of adaptation measures are expected to vary greatly, only a few governments and institutions have systematically and critically examined a portfolio of measures. As an example, some reservoirs used now as a measure for adapting to precipitation fluctuations may become unreliable in regions where long-term precipitation is projected to decrease [12.4.1]. The range of management options to cope with climate change varies largely among forest types, with some types having many more options than others [12.5.5].