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.

Cumulative net mass balance of glaciers from all European regions

-50000

-40000

-30000

-20000

-10000

0

10000

20000

30000

1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Year

cum

ula

tive

sp

ecif

ic n

et m

ass

bal

ance

(m

m)

Storglaciaeren (SE) Nigardsbreen (NO) Austre Broeggerbreen (NO)Aalfotbreen (NO) Hofsjokulln (IS) Maladeta (ES) Careser (IT) Gries (CH) Hintereis (AT) Saint Sorlin (FR) Sarennes (FR) Vernagt (AT)

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 2005.

• 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)

5.00E+06

1.00E+07

1.50E+07

2.00E+07

2.50E+07

3.00E+07

1978 1983 1988 1993 1998 2003 2008

Are

a M

elt

ed

(k

m2 )

Year

Total Melt AreaApril - October

20021998

19951991

1992

1996

2005

1987

1983

2007

2007

5.3.5 Arctic Sea Ice – key messages

• The decline in melt-season has accelerated.

Record low ice cover in Sept. 2007 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 0.5-1.0°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 !