Ice sheet surprises

A well-established relationship between the ability of the Greenland Ice Sheet to reflect sunlight and its total mass loss broke down in 2013.

“In the years 2002-2012, we saw a close correlation between variations in the ice reflectivity and how much mass was lost in total. This relation suddenly stopped in 2013. The reflectivity during the year indicated a relatively large ice loss in 2013, but the actual measurements of Greenland’s mass show that 2013 was a year with a very small loss”, says Jason Box from GEUS.

The scientists expect this new knowledge to lead to a deeper understanding of the many complicated processes that contribute to variations in the total mass of the ice sheet.

“We were quite surprised that this well-established relationship suddenly broke down, but it often works that way in science. The Greenland ice sheet is full of surprises, and we keep learning more and more of its secrets”, says Peter Langen from DMI.

The finding means that the scientists will suspend further preliminary estimates of the mass changes based on the reflectivity on the Polar Portal. Instead, they will use the actual mass loss measurements which, however, come in with several months delay. This has consequences for the estimates of the 2013 mass loss which have now to be corrected. This is documented in an addendum to the season report.