The cryosphere

Glaciers (5.3.2) Snow Cover (5.3.3) Greenland Ice Sheet (5.3.4) Arctic Sea Ice (5.3.5) Mountain Permafrost (5.3.6) Components of the Cryosphere (as described in the report)

5.3.2 Glaciers - key messages Retreat in all nine glacial European regions (vast majority of glaciers). Alps 1850 – 2006: - 2/3 of volume. (clear acceleration since 1985). More details on Norway and Svalbard; New findings of WGMS (publ. in 2008) Graph to be updated till 2006 Very likely that the glacier retreat will continue: A 3°C warming of summer air temperature could reduce the glaciers in the Alps by some 80 %. Norway: almost all small glaciers and 34% of the area projected to disappear by 2100 (SRES B2). Consequences for river flow and sea- level rise. It impacts freshwater supply, river navigation, irrigation, power- generation, tourism and winter sports. Natural hazards and damages to infrastructure.

5.3.3 Snow cover - key messages Northern hemisphere: SCE: -1.3% per decade in last 40 years, most in spring and summer. Model simulation project widespread reductions of extent and duration of snow cover in Europe over 21st century (SRES A1B, B1, A2) Impacts: Earth surface reflectivity, river discharge, vegetation, agriculture and animal husbandry, tourism, snow sports, transport and power generation.

5.3.4 Greenland ice sheet – key messages Melting more than doubled in the 1990s, probably doubled again by Accelerated movement of outlet glaciers towards the sea => 2/3 of ice loss. Larger contribution to global sea level than previously calculated: 0.14 mm/y (1993) => 0.28 mm/y (2003); to be updated (2007) Not possible to predict extent or speed of melting with any confidence (internal processes still poorly understood)

5.3.5 Arctic Sea Ice – key messages The decline in melt-season has accelerated. Record low ice cover in Sept was half the size of minimum in the 1950s. Summer ice is projected to shrink and may even disappear at the height of the melt season in the upcoming decades. There will still be substantial ice in winter. Impacts: speed up global warming, impact ocean circulation and weather patterns. Several species threatened or extinct. New economic activities: Oil and gas, shipping, tourism and fisheries - new pressures and risks to the Arctic environment.

5.3.6 Mountain permafrost – key messages Warming of mountain permafrost of °C has been observed during recent years. Present and projected atmospheric warming will lead to wide-spread thaw of mountain permafrost. Impacts: destabilization of mountain rock-walls, increase of rock fall and debris flow, problems in high-mountain infrastructure

Thank You !