Melting of Greenland's ice sheet has 'gone into overdrive'

Greenland ice sheet is melting more than it has in centuries, scientists say

Greenland's ice is melting at an alarming rate, researchers warn

Lead by glaciologist and climate scientist Luke Trusel of Rowan University, a team of USA and European researchers analyzed more than three centuries of melt patterns in ice cores from western Greenland.

"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. The author of the study, Dr Luke Trusel from US Rowan University, said: "Melting of the Greenland Ice Sheet has gone into overdrive".

"The melting and sea level rise we've observed already will be dwarfed by what may be expected in the future as climate continues to warm", he said.

Melting ice in Greenland, home to the second largest mass of ice after Antarctica, is thought to add 0.8 millimetres of water to global ocean levels annually, more than any other region, according to NASA. Researchers provided new evidence showing the impact of climate change on Arctic melting and global sea level rises, published by scientific journal Nature.

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.

'And increasing melt began around the same time as we started altering the atmosphere in the mid-1800s'. "We found a 50 percent increase in total ice sheet meltwater runoff versus the start of the industrial era, and a 30 percent increase since the 20th century alone".

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.

The research is the first continuous, multi-century analysis of melting and runoff on the ice sheet, one of the largest drivers of sea level rise globally.

"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.

But at higher elevations the summer meltwater quickly refreezes from contact with the below-freezing snowpack sitting underneath, preventing it from escaping the ice sheet in the form of runoff.

"Warming means more today than it did in the past", Trusel said in the statement.

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".

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