Online Archive

November 6, 2012 14:00 - 15:00

Empa, Dübendorf, Theodor-Erismann-Auditorium, VE102

Speakers

Prof. Dr Konrad Steffen, WSL, Birmensdorf

Leadership of diskussion

Prof. Dr Gian-Luca Bona, Empa

Content

The ice loss in Greenland shows acceleration during the last decade. The upper range of sea level rise by 2100 might be above 1 m or more on a global average, with large regional differences depending where the source of ice loss occurs. The last assessment report from the IPCC from 2007 projected a sea level rise of 18 - 59 centimeter. The numbers from the last IPCC are a lower bound because it was recognized at the time that there was a lot of uncertainty about ice sheets. The current ice loss in Greenland is close to 1 mm global sea level rise per year. Air temperatures on the Greenland ice sheet have increased by 4 deg. C since 1991. The ice sheet melt area increased by 30% for the time period 1979-2012, with record melt years in 1998, 2005, 2007, 2010, and 2012. Increase in ice velocity in the ablation region and the concurrent increase in melt water suggests that water penetrates to great depth through moulins and cracks, lubricating the bottom of the ice sheet. New insight was gained of subsurface hydrologic channels and cavities using ground penetrating radar, and a video system during the melt peak in August 2007-2010.  These new results will be discussed in view of the rapid increase in melt area and mass loss of the Greenland ice sheet due to increasing air temperatures.


CURRICULUM VITAE : KONRAD STEFFEN
Swiss Federal Research Institute WSL
Zürcherstr. 111, CH-8903 Birmendorf, Switzerland
Tel: +41 44 739 24 55; Konrad.steffen@wsl.ch, koni@ethz.ch
US and Swiss Citizen, widower and two kids
EDUCATION
Dr.sc.nat.ETH, 1983 Surface temperature distribution of an Arctic polynya: North Water in winter; advisor Prof. Dr. Atsumu Ohmura, ETH-Zürich.
Dipl.nat.ETH, 1977 Snow distribution on tundra and glaciers on Axel Heiberg Island, NWT, Canada; advisor Prof. Dr. Fritz Müller, ETH-Zürich.

The language of the presentation is English.
Free entrance, guests are welcome

 

 

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