Scientists say Greenland's icesheet shed a record amount of melted snow and ice in 2010.
A study, published in the Environmental Research Letters journal says 2010 runoff was more than twice the average annual loss in Greenland during the previous three decades, surpassing a record set in 2007.
Lead researcher Marco Tedesco, of the Cryosphere Processes Laboratory at the City College of New York, said the finding was derived from long-term satellite and observational data.
The study focused on surface melt, runoff and the number of days when bare ice, free of snow, is exposed to the Sun's radiative force.
Mr Tedesco said "melting in some areas stretched up to 50 days longer than average" in 2010.
The World Meteorological Organisation said on Thursday that last year was the warmest on record.
Summer temperatures in Greenland were 3 degrees celsius above average.