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Georg Kaser (IACS, IMGI) and Ian Allison (IACS, ACE-CRC)

Ice Changes in Antarctica,

the Himalayas and

Other Mountain Glacier Regions

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Rate of change of the surface elevation of the Antarctic Ice Sheet from satellite laser altimetry during the period 2003-2007 (Pritchard et al., 2009)

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EAIS

a) Velicogna and Wahr, 2006

Mass change after GIA correction

b) Ramillien et al., 2006

c) Velicogna 2009

Time series of Antarctic mass change estimated monthly from GRACE data. The green quadratic trend suggests a slight acceleration in loss

Antarctic estimates from GRACE

WAIS

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Mass loss from flux estimates

Rignot et al. ( 2008)

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Antarctic Ice Sheet and Sea Level Rise

0.5-0.6 mm SLE/yr (±40%)Copenhagen Diagnosis (2011)

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Causes, and future Antarctic mass loss

a. The loss from Antarctica is occurring almost solely from increased ice discharge into the ocean.

b. The cause is not well understood. One strong possibility is thinning of floating ice shelves from a warmer ocean, or changed ocean circulation, leading to acceleration of the grounded ice behind.

c. Extensive sub-glacial water in the form of lakes and active drainage systems has recently been discovered under the ice sheet. The impact of these on ice sheet dynamics is not clear.

d. Acceleration of the rate of loss from Antarctica over the next century is a strong possibility (e.g. Marine Ice Sheet instability). Accurate projections however cannot be made without better understanding of some of the dynamic processes.

e. A number of major IPY projects addressed these problems, and will contribute substantially to improving ice sheet projections.

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Glaciers and Sea Level Rise

1.2 mm SLR/yr

• glaciers out of balance with present climate: ~18 cm SLR• GL and AA ice sheets out of balance

SLR: 1 + m until 2100 …. and more meters to come in following centuries

Copenhagen Diagnosis (2011)

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Volume reduction and seaVolume reduction and sea--level equivalent (SLE) until level equivalent (SLE) until

2100 for 16 regions2100 for 16 regions

Radić & Hock (2011)

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Cogley, AnnGlac 52(59) (accepted)

Himalaya

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VERNAGTFERNER

19781998

19-Jul24-Jul

29-Jul3-Aug

8-Aug13-Aug

18-Aug23-Aug

28-Aug0

4

8

12D

isch

arge

(m

3 s-1)

Courtesy: Bayerische Akademie der Wissenschaften, Glaziologische Kommission

Glacier runoff

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Kaser et al. PNAS (2010)

Glaciers and regional water availability

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Glaciár Artesonraju, Cordillera Blanca, Peru © B. Marzeion (2010)