Scientists say the amount of meltwater running off of the Greenland ice sheet has increased in modern times because of climate change, and rapid increases could be ahead.
"From a historical perspective, today's melt rates are off the charts and this study provides the evidence to prove it", said Sarah Das, a glaciologist at Woods Hole Oceanographic Institution in MA and co-author of the study.
In July 2012, a spate of warm weather caused almost the entire surface of the Greenland ice sheet to begin melting, an event with no precedent in the satellite record.
In fact, if the sheet melting continues at "unprecedented rates", which researchers attribute to warmer summers, it could accelerate the already fast pace of sea level rise, a new study has warned.
The world's second-largest mass of ice is melting at a rate described as "off the charts" and shows no signs of abating, according to new research.
The rapid rise in surface melting over the last two decades in particular suggests a "non-linear" response to rising temperatures, meaning as global warming progresses this melting could greatly accelerate, contributing more and more to rising sea levels.
The scientists drilled at these elevations to ensure the cores would contain records of past melt intensity, allowing them to extend their records back into the 17th Century.
They found that increases in melting closely follow the start of industrial-era warming in the Arctic in the mid-1800s but the magnitude of the melt has exceeded natural variability in the past few decades.
"And increasing melt began around the same time as we started altering the atmosphere in the mid-1800s".
"We are seeing levels of Greenland ice melt and runoff that are already unprecedented over recent centuries (and likely millennia) in direct response to warming global temperatures since the pre-Industrial era", Sarah Das, co-author of the report and scientist at the USA -based Woods Hole Oceanographic Institution said in a statement.
At lower elevations, meltwater simply runs off the ice sheet, but at higher elevations some percolates down through porous, compacted snow called firn before refreezing to form layers not unlike the growth layers found in trees.
From these numbers, the researchers estimated that ice sheet-wide levels of meltwater runoff have jumped 50 per cent in the past 20 years compared with pre-industrial times.
And without a huge change of direction, Greenland "will melt more and more for every degree of warming", Mr Trusel warned.
Dr Trusel said: "To be able to answer what might happen to Greenland next, we need to understand how Greenland has already responded to climate change".
'What our ice cores show is that Greenland is now at a state where it's much more sensitive to further increases in temperature than it was even 50 years ago.