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

Changes in the climate systemPast trendsGlobal:Since the end of the 19th century, records of globalaverage temperature have shown long-termwarming trends which have been especially rapid inthe most recent decades. Relative to pre-industrialtemperatures (taken here to be comparable with theearliest observations at the end of the 19th century),three independent analyses of global averagetemperature using near-surface observation records— HadCRUT3 (Brohan et al., 2006); NOAA-NCDC(Smith et al., 2008); and NASA-GISS (Hansen et al.,2010) — show similar amounts of warming by the2002 to 2011 decade of 0.77 °C, 0.78 °C and 0.80 °C,respectively (Figure 2.5 left). This magnitude ofwarming corresponds to more than one third of the2 °C warming permitted under the global climatestabilisation target of the EU and UNFCCC.Figure 2.5 (left) shows estimates (based oninstrumental measurements) of air temperatures at2 m height over land, and sea surface temperaturesobserved from ships and buoys. The variousestimates differ slightly because the underlyingsources differ in their methods for analysing thedata and filling data gaps. Another independentmethod that can be used to estimate changes inglobal average temperature is through 'Climatereanalysis' (see Box 2.2).The rate of change in global average temperatureduring the last century was on average around0.07 °C per decade (for all three analyses shownin Figure 2.5). The rate of change increased toaround 0.15 °C per decade averaged over the past50 years, and between 0.17 and 0.22 °C over the last20 years (Figure 2.5 right). This rate is close to theindicative limit of 0.2 °C per decade proposed bysome scientific studies (WBGU, 2003; van Vliet andLeemans, 2005).Figure 2.5 Change in global average temperature from three sources (1850–2011)Global average temperature change (°C)relative to pre-industrialRate of change (°C/decade)0.50.20.00.50.1– 0.50.0– 0.1– 1.01850 1900 1950 2000Met Office Hadley Centre and UEA ClimaticResearch UnitNOAA National Climatic Data CenterNASA Goddard Institute for Space Studies0.0– 0.21850 1900 1950 2000Met Office Hadley Centre and UEA ClimaticResearch UnitNOAA National Climatic Data CenterNASA Goddard Institute for Space StudiesNote:Change (left) and rates of change, based on 10-year running average (right) in global average air temperature. Temperatureis expressed in degrees Celsius (°C) relative to a pre-industrial baseline period. The upper time series on the left graph showsannual anomalies and the lower time series shows decadal average anomalies for the same datasets.Source: 1) Black line — HadCRUT3 from the UK Met Office Hadley Centre and University of East Anglia Climate Research Unit,baseline period 1850–1899 (Brohan et al., 2006). The grey area represents the 95 % confidence range.2) Red line — MLOST from the US National Oceanic and Atmospheric Administration (NOAA) National Climatic Data Center,baseline period 1880–1899 (Smith et al., 2008).3) Blue line — GISSTemp from the National Aeronautics and Space Administration (NASA) Goddard Institute for SpaceStudies, baseline period 1880–1899 (Hansen et al., 2010).Climate change, impacts and vulnerability in Europe 201257