Scientists ‘stunned’ by plants found a mile under Greenland icesheet, revealing previous total ice loss

If all the ice on Greenland melted immediately, the world would experience around 20 feet of sea level rise, which would devastate coastal population centres around the world, displacing millions of people.

Now a “troubling” new discovery has revealed that in previous periods of warming - which charted a course not dissimilar to the human-caused climate crisis currently underway - this is precisely what happened.

The evidence was stumbled upon quite by accident, after the rediscovery of long lost cores drilled through the ice back in the mid-1960s.

In 1966, US Army scientists drilled down through almost a mile of ice in northwestern Greenland, until they hit what lies beneath Greenland’s enormous ice sheet.

The resulting core they pulled up was a fifteen-foot-long “tube of dirt”. The frozen sediment they extracted was apparently then locked away in a freezer and never studied.

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However, after more than 50 years it was found and properly examined. The astonishing contents of the core now add to the urgency with which our species must act to tackle the causes of the climate crisis.

In 2019, University of Vermont scientist Andrew Christ looked at it through his microscope and couldn’t believe what he was seeing.

It was not just a tube of dirt, but instead he found twigs and leaves amongst the sand and rock.

The findings indicate that in the recent geologic past a vegetated landscape, perhaps a boreal forest, stood where a mile-deep ice sheet as big as Alaska stands today.

Dr Christ and his colleagues’ results show that most, or all, of Greenland must have been ice-free within the last million years, perhaps even the last few hundred-thousand years.

"Ice sheets typically pulverize and destroy everything in their path," said Dr Christ.

“But what we discovered was delicate plant structures perfectly preserved.

“They’re fossils, but they look like they died yesterday. It’s a time capsule of what used to live on Greenland that we wouldn’t be able to find anywhere else.”

The scientists said understanding the behaviour of the Greenland Ice Sheet in the past is critical for predicting how it will respond to the changing climate in the future and how quickly it will melt.

Since some twenty feet of sea-level rise is tied up in Greenland’s ice, every coastal city in the world is at risk.

They said the research “provides the strongest evidence yet that Greenland is more fragile and sensitive to climate change than previously understood, and at grave risk of irreversibly melting off.”

“This is not a twenty-generation problem,” said Professor Paul Bierman, a geoscientist at UVM.

“This is an urgent problem for the next 50 years.”

In their paper, the researchers said that much of the Pleistocene - the icy period covering the last 2.6 million years - large portions of the ice on Greenland persisted even during warmer spells called “interglacials”.

But the extent of Greenland’s ice sheet and what kinds of ecosystems existed there before the last interglacial warm period, which ended about 120,000 years ago, have been hotly debated and poorly understood.

The new study makes clear that the deep ice at Camp Century - where the core was extracted, some 75 miles inland from the coast and only 800 miles from the North Pole - entirely melted at least once within the last million years and was covered with vegetation, including moss and perhaps trees.

“Our study shows that Greenland is much more sensitive to natural climate warming than we used to think, and we already know that humanity’s out of control warming of the planet hugely exceeds the natural rate,” said Dr Christ.

His warning was echoed by Professor Bierman: “Greenland may seem far away, but it can quickly melt, pouring enough into the oceans that New York, Miami, Dhaka - pick your city - will go underwater.”

The research is published in the Proceedings of the National Academy of Sciences.