New melt record for Greenland Ice Sheet

Posted: 22 January 2011

New research shows that 2010 set new records for the melting of the Greenland Ice Sheet, expected to be a major contributor to projected sea level rises in coming decades.

"This past melt season was exceptional, with melting in some areas stretching up to 50 days longer than average,” said Dr. Marco Tedesco, Director of the Cryosphere Processes Laboratory at the City College of New York (CCNY – CUNY), who is leading a project studying variables that affect ice sheet melting.

Greenland melting index
The standardized melting index anomaly for the period 1979–2010.

“Melting in 2010 started exceptionally early at the end of April and ended quite late in mid- September.”

The study, with different aspects sponsored by WWF, the US National Science Foundation (NSF) and NASA, examined surface temperature anomalies over the Greenland ice sheet surface, as well as estimates of surface melting from satellite data, ground observations and models.

In an article published in Environmental Research Letters, Dr Tedesco and co-authors note that in 2010, summer temperatures up to 3?C above the average were combined with reduced snowfall.

The capital of Greenland, Nuuk, had the warmest spring and summer since records began in 1873.

Bare ice was exposed earlier than the average and longer than previous years, contributing to the extreme record.

“Bare ice is much darker than snow and absorbs more solar radiation,” said Dr Tedesco. ““This means the old ice is warming, melting, and running off into the sea."

Greenland Ice Sheet - aupraglacial lake
A supraglacial lake on the Greenland Ice Sheet. Note the streams feeding the lake and the darker area at the bottom. This could be cryoconite, a dark mixture of soot, sediments and organic matter. Photo credit: WWF/M. Tedesco

“Other ice melting feedback loops that we are examining include the impact of lakes on the glacial surface, of dust and soot deposited over the ice sheet and how surface meltwater affects the flow of the ice toward the ocean.”

WWF climate specialist Dr. Martin Sommerkorn said “Sea level rise is expected to top 1 metre by 2100, largely due to melting from ice sheets. And it will not stop there – the longer we take to limit greenhouse gas production, the more melting and water level rise will continue.”
 

Dr. Tedesco’s continuing research on ice sheets can be followed on www.cryocity.org

For more on Arctic climate change, visit www.panda.org/arctic