WORKSHEET The melting glaciers - Glacial lake outburst floods in Nepal and Switzerland 2 GERMANWATCH M 2 Mass balance of glaciers and 9 mountainous regions on Earth (1975 – 2003) Mean annual mass balance (mm) Mean accumulated mass balance (mm) 500 Growth in mass -1.000 250 Loss of mass -2.000 -3.000 -250 Loss of mass -4.000 -500 -5.000 -750 -6.000 Mountainous regions -1.000 -7.000 A Average from 9 mountainous regions O Average from 30 glaciers -1.250 -8.000 -1.500 -9.000 1975 1980 1985 1990 1995 2000 2005 1975 1980 1985 1990 1995 2000 2005 (Source: Maisch, M. and W. Haeberli (2003): Die rezente Erwärmung der Atmosphäre - Folgen für die Schweizer Gletscher. In: Geographische Rundschau 55(2), p. 8, acc. to data from the WGMS, World Glacier Monitoring Service, Zürich; updated to 2003.) M 3 Glacier melting Since the end of the Second World War, mass balances of three quarters of the measured values were between minus 1 and minus 30 metres" wrote ETH glaciologist glaciers have been measured on a yearly basis worldwide. Alone in the period between 2003 and 2009, a loss of mass (not including the Antarctic and Greenland ice) of around 350 kg per square metre and year was identified. Recent Andreas Bauder [...]. The national retreat record was bro- ken in the most recent measuring period by the Roseg Glacier. In only one year, it lost 1,305 metres in length. This means that the Grisons glacier has retreated from 6,711 to 2,567 metres since measurements began (1855). This is apparent from the newest data from the Swiss Academy of Sciences (Scnat) [...J. The report also states that the Alpine glaciers are currently losing around two to three percent of their surface area each year (in 2011 this was around 1,800 km²) and their volume (in 2011 this measurements in Switzerland tie in with this trend. CC The values ascertained for the 2010/2011 period show that the glaciers in Switzerland continue to retreat rapidly. "A total of 93 from 97 glaciers observed have lost in both length and mass. Three of them did not change their position and only one glacier – the Glacier du Mont Durand in Valais – moved forward 23 metres. Around was around 80 ± 20 km³). 9 (Sources: IPCC (2013): Climate Change 2013: The Physical Science Basis. Working Group 1 Contribution to the IPCC Fifth Assessment Report. Chapter 4 (draft); own translation of "Tagesanzeiger" 14.10.2012: Gletscherschmelze schreitet voran. http://www.tagesanzeiger.ch/wissen/natur/Gletscherschmelze-schreitet-voran/story/20714307, accessed 27.01.2014) A-A A-A M 4 Increased melting of land ice Ice, glaciers and snow are melting at an ever faster rate June since 2008 (ESA Envisat). The outcomes of this de- because of increasing average temperatures. Kilimanjaro velopment are on the one hand a loss of drinking water reservoirs and, on the other hand, changes to the natural water supply. This often has more severe consequences in tropical and sub-tropical regions with sensitive ecosys- in Tanzania, for example, has lost more than 85% of its gla- cial surface area to date; first measurements were taken in 1912. Snow cover on the planet as a whole has decreased by more than 10% since 1860. In Europe and Asia, snow cover on land has reached new record low levels every tems than in the north.