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

Climate impacts on environmental systemsMap 3.4 Trend in relative sea level at selected European tide gauge stations (1970–2010)-30°-20°-10°0°10°20°30°40°50°60°70°Trend in relative sealevel at selectedEuropean tide-gaugestations, 1970–2010Trend, mm/year60°< – 4– 4 to – 2– 2 to – 150°– 1 to – 0.5– 0.5 to 0.50.5 to 150°1 to 22 to 4> 440°40°0 500 0° 1000 150010°km20°30°40°Note:These measured trends are not corrected for local land movement. No attempt has been made to assess the validity of anyindividual fit, so results should not be treated as suitable for use in planning or policymaking.Source: Woodworth and Player, 2003; Permanent Service for Mean Sea Level (PSMSL), 2012; 'Tide Gauge Data' (http://www.psmsl.org/products/trends).satellite measurements are not. In particular, thelands around the northern Baltic Sea are still risingsince the last ice age due to the post-glacial rebound(Johansson et al., 2002).A significant recent step forward in projectingfuture sea levels is an improved understanding ofthe contributions to recent sea-level rise. A recentstudy found good agreement over the four lastdecades between observed total global sea-levelrise and the sum of known contributions (Churchand White, 2011). Table 3.1 summarises the maincontributions based on that study. According to thistable, thermal expansion was likely to have beenthe most important contributor to sea-level risethroughout the whole period (1972–2008). Sea-levelrise has accelerated in the latter part of that period(1993–2008) when the melting of glaciers and icecaps became the most important source of sea-levelrise.ProjectionsCurrently there are two main approaches toprojecting future sea level: physically-based modelsthat represent the most important known processes,and statistical models that apply the observedrelationship between temperature or radiativeforcing on the one hand and sea level on the otherhand in the past and extrapolate it to the future.Both approaches produce a spread of results, whichresults in large uncertainties around future sea-levelrise.The IPCC AR4 contained several statements onfuture sea level. Most often quoted is the rangeof sea-level rise projected by physically-basedmodels for thermal expansion, glaciers and smallice caps, the mass balance of the Greenland andWest Antarctic ice sheet, and a term to representthe observed dynamic acceleration of the melting ofthe major ice sheets. The result is a global averageClimate change, impacts and vulnerability in Europe 2012105