Greenland's ice is melting at an 'unprecedented rate'

Federico Mansilla
Diciembre 6, 2018

Fellow glaciologist and co-author of the report Sarah Das said: "From a historical perspective, today's melt rates are off the charts, and this study provides the evidence to prove this".

They showed that melting of Greenland's surface ice began increasing in the mid-19th century and then ramped up dramatically during the 20th and early 21st centuries.

Das and her colleagues at Rowan University and elsewhere reached that conclusion by examining three ice cores from central west Greenland, and one from an ice cap off the coast, that contain a history of melt events spanning the past 350 years.

Because of a "nonlinear response of surface melting to increasing summer air temperatures, continued atmospheric warming will lead to rapid increases in [Greenland ice sheet] runoff and sea-level contributions", the study said.

The long-term record the researchers built from these layered ice cores allowed them to spot a slight trend of increased melting across Greenland coinciding with the beginning of modern-day warming in the mid-1800s.

The researchers warned that their findings also showed that it would only take a little additional warming to cause ice sheet melting to spike and sea levels to rise.

At lower elevations, where melting is the most intense, meltwater runs off the ice sheet and contributes to sea level rise, but no record of the melt remains.

'We found a 50% increase in total ice sheet meltwater runoff versus the start of the industrial era, and a 30 per cent increase since the 20th Century alone'. The author of the study, Dr Luke Trusel from US Rowan University, said: "Melting of the Greenland Ice Sheet has gone into overdrive".

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"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.

The increased melting began around the same time humans started altering the atmosphere in the mid-1800s, said Trusel, lead author of a study of the meltwater runoff that was published Wednesday in the journal Nature.

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.

Instead, it forms distinct icy bands that stack up in layers of densely packed ice over time.

'Warming means more today than it did in the past.'=.

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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