In a bizarre story of lost and found, scientists have unraveled Greenland’s secret – It really might have been forest green only a million years ago.
An international team of scientists, led by Paul Bierman of the University of Vermont, analysed a mile deep, 54-year-old sample of plant fossil filled dirt taken from below Greenland’s ice. They found that the abundance of plant fossils may have meant Greenland was ice free within the last million years – potentially even only a few hundred thousand years ago.
Key research points
- Fossilised plants found in dirt sample below Greenland ice
- Plant material suggests Greenland was ice free in the last million years
- If Greenland was unexpectedly ice free, the ice may be sensitive to melting
The fifteen-foot dirt sample was originally taken in 1966 but got lost in a freezer. When it was rediscovered in 2019, Andrew Christ examined the dirt sample under a microscope and found it was packed full of twigs and leaves instead of just sand and rock.
“Ice sheets typically pulverize and destroy everything in their path,” says 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.”
In their paper, published in Proceedings of the National Academy of Sciences, they show that Greenland was ice-free at some time during the Pleistocene – 2.6 million years of repeated glaciation with short peaks of warmth that ended around 120,000 years ago. The Pleistocene was considered a colder time than now, so the ice in Greenland may be very sensitive to a temperature variation, suggesting we could experience another similar melt as our current climate warms, too.
Since the melting ice on Greenland is a contributor to sea levels, learning how Greenland was affected by a quick ice melt helps refine predictive models for the changes we are seeing today.
“Greenland may seem far away,” says Bierman, “but it can quickly melt, pouring enough into the oceans that New York, Miami, Dhaka – pick your city – will go underwater.”
“This is not a twenty-generation problem. This is an urgent problem for the next 50 years.”
Dr Deborah Devis is a science journalist at The Royal Institution of Australia.
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