Climate change, impacts and vulnerability in Europe ... - MemoFin.fr

Climate impacts on socio-economic systems and healthcan also enhance the risk of forest decline, ifcritical loads are exceeded. The concentrationsof nitrogen oxides due to fossil fuel combustionare still high in spite of increased use of catalyticconvertors. The high concentrations of reducednitrogen from intensive agriculture, like ammoniaare still a matter of concern for forests in the aircausing eutrophication (Sutton, 2011). Increasesin ground‐level ozone are likely in some regionsdue to warmer temperatures, which would cause adecrease in forest health and growth, which in turnhas critical implications for forest distributions andfuture rates of carbon sequestration (Matyssek et al.,2012).In general, forest productivity is projected toincrease in areas with increased water availability,if appropriate tree species are growing there, whileit is projected to decrease where water is scarce andprojected to decline further. Wherever droughtsincrease, forest productivity is expected to decrease.Overall, climate change is projected to have a positiveeffect on the growing stocks in northern Europe anda negative effect in some regions in southern Europe.However, quantitative projections are not currentlyavailable as existing studies on future climate impactson forests focus on effects on individual species.Box 4.1 provides quantitative projections of forestcomposition and their economic impacts.Box 4.1Projected changes in forest composition and their economic impactsClimate change is expected to strongly affect the biological and economic viability of different tree species inEurope. A recent modelling study assessed the impacts of projected climate change on forest composition acrossEurope as well as the economic consequences in terms of annual productivity and land value (Hanewinkel et al.,2012). The major commercial tree species in Europe, Norway spruce, shifts northward and to higher altitude.It loses large parts of its present range in central, eastern and western Europe under all climate scenarios(SRES A1B, A1FI, and B2). Depending on the emission scenario and climate model, between 21 % and 60 %(mean: 34 %) of European forest lands will be suitable only for a Mediterranean oak forest type with low economicreturns by 2100, compared to 11 % in the baseline period 1961–1990. Further information on major groups oftree species is provided in Figure 4.2. As a result of the decline of economically valuable species, the value offorest land in Europe is projected to decrease between 14 % and 50 % (mean: 28 % for an interest rate of 2 %)by 2100. The economic loss is estimated at several hundred billion EUR.Figure 4.2Projected change in the share of major tree species in EuropeNote:The bars reflect the standard deviation resulting from four different climate model realisations of the SRES A1B emissionscenario. The relative size of the icons corresponds to the relative height of mature trees of the species groups.For additional information see the original reference. Europe refers to the area covered by the ENSEMBLE climateprojections.Source: Hanewinkel et al., 2012. © Nature Publishing Group. Reprinted with permission.176 Climate change, impacts and vulnerability in Europe 2012