Plants have been found preserved beneath mile-deep Greenland ice, according to a new study from the University of Vermont. The experts believe that in the recent geologic history of Greenland, a vegetated landscape stood where an ice sheet as big as Alaska stands today.
The research confirms the troubling realization that Greenland’s ice has melted off entirely during warm periods like the one we are now experiencing as a result of human-induced climate change.
With 20 feet of potential sea level rise frozen in the Greenland Ice Sheet, every coastal city in the world is at its mercy. In order to predict how the quickly the ice will melt in the future, it is critical for scientists to understand the ice sheet’s behavior in the past.
The new study provides the strongest evidence yet that Greenland is more sensitive to climate change than what was previously expected.
“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 UVM scientist Andrew Christ.
In 1966, the U.S. Army drilled down through nearly a mile of ice in northwestern Greenland. A massive sediment sample was recovered, but then lost in a freezer for decades.
Two years ago, Christ examined the sediment under a microscope. He was stunned to see twigs and leaves instead of just sand and rock.
In collaboration with an international team of researchers, Christ has been analyzing these fossil plants. The findings suggest that most, or all, of Greenland was ice-free within the last few hundred-thousand years.
“Ice sheets typically pulverize and destroy everything in their path, but what we discovered was delicate plant structures – perfectly preserved,” said Christ. “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 sediment sample examined for the study was pulled up from beneath the ice at Camp Century, located 75 miles inland from the coast and only 800 miles from the North Pole. The team’s findings suggest that this ice completely vanished at least once within the last million years and was covered with vegetation, perhaps even a forest.
“This is not a twenty-generation problem,” said Paul Bierman, a geoscientist at UVM. “This is an urgent problem for the next 50 years.”
“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 study is published in the journal Proceedings of the National Academy of Sciences.
By Chrissy Sexton, Earth.com Staff Writer