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

Climate impacts on socio-economic systems and healthImpacts of climate change, combined withincreasing atmospheric CO 2concentrations, onforests vary across regions. In some areas, forestsmay grow faster as a result of increased availabilityof CO 2and higher temperature (and concurrentincreases in nitrogen availability). In others areas,especially those receiving less precipitation, forestsmay suffer and experience decreased growth.Climate change may also enhance the frequencyof favourable conditions for forest fires extendingthe fire season in both time and space. The uniqueadaptation of boreal forests makes them moresensitive to temperature fluctuations than temperateor other forests. Even a slight increase in meanannual temperature is enough to affect manyspecies' growth and regeneration. The boreal forestis likely to decrease in area, biomass and carbonstock, with a significant disruption at its southernboundary but the northern border line will movefurther north (Olsson, 2009; Hanewinkel et al., 2012).Selection of indicatorsThis section presents the following indicators thatcapture climate-sensitive characteristics of foreststhat are relevant for forest management:• Forest growth: This indicator describes the extentof forests (i.e. their area) as well as the growingstock (i.e. the volume of the abovegroundbiomass of all living trees). The definitions referto the Forest Europe definitions (Forest Europe,UNECE and FAO, 2011). These definitionsare currently being refined by the EuropeanNational Forest Inventory network (ENFIN) toallow for better comparison of forest-relatedinformation across Europe.• Forest fires: This indicator monitors the areasburnt by forest fires, which are experiencedin many European countries, in particular insouthern Europe. Climate change may leadto more forest fires due to warmer and drierweather, and possibly increases in lightningstorms (a natural cause of fires).Forest carbon stock would be another potentialindicator related to forests. The forests in EEAEurope contain more than 26 000 Mt C; about halfof that amount is stored in soils (Forest Europe,UNECE and FAO, 2011). Furthermore, temperateand boreal forests are the main terrestrial carbonsink worldwide (Houghton, 2003). Biomass growthin European forests (including also countriesbeyond the EEA region) is estimated to sequesterabout 10 % of the GHG emissions from that region.Climate-driven changes in the forest carbon stockare a potential feedback mechanism that could eitheraccelerate or slow down anthropogenic climatechange. A comprehensive assessment of the state ofEurope's forests, including their carbon stock, hasrecently been completed (Forest Europe, UNECEand FAO, 2011). This assessment concluded, amongothers, that the carbon stock of European forests iscurrently growing, at a rate of more than 100 Mt Cper year between 1990 and 2010. This increase is dueto changes in forest management and environmentalchanges including climate, CO 2, and nitrogendeposition. In order not to repeat information readyavailable elsewhere, this EEA report does not presentan indicator on forest carbon stock but refers to theoriginal study for more detailed information. Finally,an indicator on forest health could be conceived(Moore and Allard, 2008) but such information is notcurrently available across Europe.Data quality and data needsForest areas of most European countries areinventoried by National Forest Inventories(NFIs) as well as by the monitoring activities ofthe International Co-operative Programme onAssessment and Monitoring of Air Pollution Effectson Forests (ICP Forests ( 55 )). Time series of forest datago back to more than 100 years for some Europeancountries. Independent periodic assessments of forestarea, growing stock and increment as well as carbonstock are conducted through systematic observationwith statistically designed sampling based on theNFIs. The quality of the data is high. However, theestimates of the inventory of each country may differdue to differences in the definition of the variables.Harmonisation efforts are ongoing to make the forestinformation comparable and representative of theforests in Europe. The work is conducted by theENFIN in COST Actions E43 and FP1001 (McRobertset al., 2010).It is very difficult to separate the impacts of climatechange on forests and forestry from non‐climateinfluences (e.g. related to management) inobservational data. Therefore, efforts to understandthe impacts of climate change on forests and forestryare largely based on controlled experiments inlaboratories and on small forest plots, and on modelsimulations.( 55 ) See http://icp-forests.net.Climate change, impacts and vulnerability in Europe 2012173