A dark future

Andreas P. Ahlstrøm, Senior Scientist, GEUS & Jason E. Box, Professor, GEUS

The Greenland Ice Sheet is facing a darker future. The snow on the surface of the Greenland ice sheet has become more than 5% darker over the last decade – and a darker surface brings more trapped sunlight that in turn increases melting. When fresh snow warms up snow crystals become rounded and absorb more energy from the Sun. Until recently, this has been the only explanation for the gradual darkening of the surface, but now a new study show that windblown dust has played an increasingly important role since 2009. The reason is believed to be the shortening of the snow cover season in the Northern Hemisphere, causing dust to be blown onto the ice sheet surface earlier in the spring.

Minister for Climate, Energy and Building Rasmus Helveg Petersen studies the darker ice during a visit to a PROMICE climate station on the ice sheet in South Greenland, informed by Senior Scientist Andreas Ahlstrøm from GEUS. Visit the same station yourself by clicking on the picture. Picture: Louise Sprotte-Hansen, KEBMIN.
Left side: a PROMICE climate station on the ice sheet surface. From left to right: GEUS Director Johnny Fredericia, Senior Scientist Andreas Ahlstrøm, Permanent Secretary of State Thomas Egebo, Minister for Climate, Energy and Building Rasmus Helveg Petersen (RV), Naalakkersuisoq for Environment and Nature Kim Kielsen (Siumut), Head of Dept. Rikke Thoning, Programme Coordinator Morten Skovgaard Olsen, Head of Dept. Karen Arleth. Picture: Louise Sprotte-Hansen, KEBMIN.


Dumont, M., E. Brun, G. Picard, M. Michou, Q. Libois, J-R. Petit, M. Geyer, S. Morin & B. Josse. 2014. Contribution of light-absorbing impurities in snow to Greenland's darkening since 2009, Nature Geoscience 7, 509–512, doi 10.1038/ngeo2180

Box, J.E.,  J. Cappelen, C. Chen, D. Decker, X. Fettweis, T. Mote, M. Tedesco, R.S.W. van de Wal, J. Wahr. 2013. Greenland Ice Sheet in Arctic Report Card 2012.