IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group II: Impacts, Adaptation and Vulnerability

Executive summary

Many of the results reported here are based on a range of emissions scenarios extending up to the end of the 21st century and assume no specific climate policies to mitigate greenhouse gas emissions.

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 both the cryosphere (retreat of glaciers and extent of permafrost) as well as natural and managed ecosystems (lengthening of growing season, shift of species) [12.2.1]. Another example is the European heatwave in 2003 which had major impacts on biophysical systems and society [12.6.1]. The observed changes are consistent with projections of impacts due to climate change [12.4].

Climate-related hazards will mostly increase, although changes will vary geographically (very high confidence).

Winter floods are likely to increase in maritime regions and flash floods are likely to increase throughout Europe [12.4.1]. Coastal flooding related to increasing storminess and sea-level rise is likely to threaten up to 1.6 million additional people annually [12.4.2]. Warmer, drier conditions will lead to more frequent and prolonged droughts, as well as to a longer fire season and increased fire risk, particularly in the Mediterranean region [,]. During dry years, catastrophic fires are expected on drained peatlands in central Europe [12.4.5]. The frequency of rock falls will increase due to destabilisation of mountain walls by rising temperatures and melting of permafrost [12.4.3].Without adaptive measures, risks to health due to more frequent heatwaves, particularly in central and southern Europe, and flooding, and greater exposure to vector- and food-borne diseases are anticipated to increase [, 12.6.1]. Some impacts may be positive, as in reduced risk of extreme cold events because of increasing winter temperatures. However, on balance, health risks are very likely to increase [12.4.11].

Climate change is likely to magnify regional differences of Europe’s natural resources and assets (very high confidence).

Climate scenarios indicate significant warming, greater in winter in the North and in summer in southern and central Europe [12.3.1]. Mean annual precipitation is projected to increase in the North and decrease in the South [12.3.1]. 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-eastern Europe []. Forests are projected to expand in the North and retreat in the South []. Forest productivity and total biomass is likely to increase in the North and decrease in central Europe, while tree mortality is likely to accelerate in the South []. Differences in water availability between regions are anticipated to become sharper (annual average runoff increases in the North and North-west, and to decrease in the South and South-east) [12.4.1].

Water stress will increase, as well as the number of people living in river basins under high water stress (high confidence).

Water stress will increase over central and southern Europe. The percentage area under high water stress is likely to increase from 19% today to 35% by the 2070s, and the additional number of people affected by the 2070s is expected to be between 16 millions and 44 millions [12.4.1]. The most affected regions are southern Europe and some parts of central and eastern Europe, where summer flows may be reduced by up to 80% [12.4.1]. The hydropower potential of Europe is expected to decline on average by 6% but by 20 to 50% around the Mediterranean by the 2070s [].

It is anticipated that Europe’s natural (eco)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 the loss of up to 20% of coastal wetlands [12.4.2], reducing 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 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 to shrink [12.4.5]. Recruitment and production of marine fisheries in the North Atlantic are likely to increase []. The northward expansion of forests is projected to reduce current tundra areas under some scenarios [12.4.4]. Mountain plant communities face up to a 60% loss of species under high emissions scenarios [12.4.3]. A large percentage of the European flora 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 conser-vation may be needed because climate change is very likely to alter conditions of suitability for many species in current sites [12.5.6].

Climate change is estimated to pose challenges to many European economic sectors and is expected to alter the distribution of economic activity (high confidence).

Agriculture will have to cope with increasing water demand for irrigation in southern Europe, and with 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: around the Mediterranean, two to three fewer weeks in a year will require heating but an additional two to five weeks will need cooling by 2050 []. Peak electricity demand is likely to shift in some locations from winter to summer []. 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 [12.4.9].

Adaptation to climate change is likely to benefit from experiences gained in reaction to extreme climate events, by specifically implementing proactive climate change risk management adaptation plans (high confidence).

Since the Third Assessment Report, governments have increased greatly 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 towards more proactive risk management. A prominent example is the implementation in several countries of early warning systems for heatwaves [12.6.1]. Other actions have addressed long-term climate changes. 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 showed that crops that become less economically viable under climate change can be replaced profitably 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 (very high confidence).

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]. In terms of forestry, the range of management options to cope with climate change varies largely among forest types, some having many more options than others [12.5.4].