CRYOSPHERE CHANGES

• These slides show photographs and images so that you can learn about how the cryosphere is being affected by climate change today.

• You can refresh your knowledge of what is meant by the ‘cryosphere’ by visiting the Discovering The Arctic website: http://www.discoveringthearctic.org.uk/9_what.html

Collapse of West Antarctic ice shelves: Larsen B, bigger than the US state of Rhode Island (or Cornwall), disintegrated in 2002.

http://commons.wikimedia.org/wiki/File:Larsen_B_Collapse_Size_Comparison.png Robert A. Rohde

See the next slide for the former location of this ice shelf.

Satelliteimage

NASA satellite infrared sensor data: this shows the pattern of warming across the snow, ice, and sea

surfaces in the Antarctic region from 1981 to 2007.

http://commons.wikimedia.org/wiki/File:Antarctic_Temperature_Trend_1981-2007.jpg

20th century global average temperature rise of about 0.7ºC. In parts of WestAntarctica and the Arctic, temperature has risen by over 3°C in the last 50 years.

http://scienceblogs.com/significantfigures/index.php/2013/04/02/three-iconic-graphs-showing-the-climate-fix-were-in/

The ‘0’ here refers to the average temperatureover the time of recordings.

Each year Arctic sea ice reaches its lowest extent in September (by end of the summer). Notice how this trend compares with the

temperature trend in the previous slide.

http://nsidc.org/arcticseaicenews/2013/10/

The white area of the map shows Arctic sea ice extent in September 2013. The magenta line around it shows

the 1981 to 2010 median.

http://commons.wikimedia.org/wiki/File:Arctic_ice.jpg?uselang=en-gbPatrick Kelley

http://nsidc.org/arcticseaicenews/2013/10/

Photo showing break up of sea ice.

North Pole

Greenland ice sheet

In addition to becoming less extensive, Arctic sea ice has become thinner and will continue to thin this century.

http://commons.wikimedia.org/wiki/File:Arctic_Ice_Thickness.png?uselang=en-gb

NOAA image

View of Mont Blanc, near Chamonix, France. Since AD 1850 the total area of the Alps covered by glacier ice has halved.

http://commons.wikimedia.org/wiki/Chamonix#mediaviewer/File:Mont_Blanc_100_0068.JPG (Daniel D.)

1938-2009 comparison: Grinnell Glacier, Montana, USA.

Melting glacier images

http://commons.wikimedia.org/wiki/File:Grinnell_Glacier_1938-2009.jpg?uselang=en-gb (T.J.Hileman 1938, Lindsey Bengtson 2009)

Retreat of the calving edge of the Jakobshaven outlet glacier, Greenland, between 1851 and 2006.

Melting glacier images

NASAimageThe sea is

on this side.

Interior ofGreenlandis on thisside.

http://commons.wikimedia.org/wiki/File:Jakobshavn_retreat-1851-2006.jpg?uselang=en-gb

http://nsidc.org/cryosphere/sotc/glacier_balance.html

1941-2004 comparison: Glacier Bay National Park and Reserve's White Thunder Ridge (Alaska) as seen on August 13, 1941 (left) and August 31, 2004 (right). Muir Glacier has retreated out of the field of view, Riggs Glacier has thinned and retreated significantly, and dense new vegetation has appeared. Muir Glacier was more than 2,000 feet thick in 1941. 2004 USGS photo by B. F. Molnia; 1941 photo by W. O. Field.

Melting glacier images

Kenai Fjords National Park, Alaska. This glacier still exists but has retreated 20 km back from the 1909 position and is out of view in the 2004 photo.

Melting glacier images

http://commons.wikimedia.org/wiki/File:McCarty_Glacier.jpg?uselang=en-gb Ulysses S. Grant 1909, Bruce Molnia, 2004)

1993-2000 comparison: Over 80% of the ice and snow on Mount Kilimanjaro, Tanzania, has disappeared over the past century, much of it in the past few decades (NASA Landsat 5 images).

Melting glacier images

http://commons.wikimedia.org/wiki/File:Snow_and_Ice_on_Kilimanjaro-1993.jpg?uselang=en-gb

http://commons.wikimedia.org/wiki/File:Snow_and_Ice_on_Kilimanjaro-2000.jpg?uselang=en-gb

This map shows changes to glacier mass balance in mountain regions between 1970 and 2004. Notice the anomaly of Scandinavia which has some

glaciers that thickened during the time period of measurement.

http://commons.wikimedia.org/wiki/File:Glacier_Mass_Balance_Map.png (Robert A. Rohde)

New Zealand

83% of thesurveyedglaciersshowedthinning.

http://commons.wikimedia.org/wiki/File:AntarcticaTemps_1957-2006.jpg?uselang=en-gb NASA image

Notice from the colour difference how West Antarctica is being affected by more warmingthan East Antarctica. Much of East Antarctica has experienced little, if any, change.

Map of temperature rise across Antarctica from 1957 to 2006.

West Antarcticice sheet

East Antarcticice sheet

Some clues for understanding why the West Antarctic ice sheet is more sensitive to climate

change than the East Antarctic ice sheet

• The East Antarctic Ice Sheet (EAIS) has about 9 times the volume of the West Antarctic Ice Sheet (WAIS)

• The EAIS has an average thickness of 2,226 metres compared with the WAIS maximum of 1,306 metres.

• The EAIS reaches a higher elevation above sea level (over 4,000 metres) than the WAIS.

• In contrast with East Antarctica, the WAIS sits on bedrock that is mostly below sea level.