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Seeds, twigs and insect parts in ice core stun scientists and confirm that center of ice sheet was melted in recent past
Photo by Jon Vidar Sigurdsson, via Flickr
by Joshua Brown, in UVM Today
The story of Greenland keeps getting greener—and scarier.
A new studyprovides the first direct evidence that the center—not just the edges—of Greenland’s ice sheet melted away in the recent geological past and the now-ice-covered island was then home to a green, tundra landscape.
A team of scientists re-examined a few inches of sediment from the bottom of a two-mile-deep ice core extracted at the very center of Greenland in 1993—and held for 30 years in a Colorado storage facility. They were amazed to discover soil that contained willow wood, insect parts, fungi, and a poppy seed in pristine condition.
“These fossils are beautiful,” says Paul Bierman, a scientist at the University of Vermont who co-led the new study with UVM graduate student Halley Mastro and nine other researchers, “but, yes, we go from bad to worse,” in what this implies about the impact of human-caused climate change on the melting of the Greenland ice sheet.
The study, published in the Proceedings of the National Academy of Sciences on August 5th, confirms that Greenland’s ice melted and the island greened during a prior warm period likely within the last million years—suggesting that the giant ice sheet is more fragile than scientists had realized until the last few years.
If the ice covering the center of the island was melted, then most of the rest of it had to be melted too. “And probably for many thousands of years,” Bierman said, enough time for soil to form and an ecosystem to take root.
“This new study confirms and extends that a lot of sea-level rise occurred at a time when causes of warming were not especially extreme,” said Richard Alley, a leading climate scientist at Penn State who reviewed the new research, “providing a warning of what damages we might cause if we continue to warm the climate.”
Sea level today is rising more than an inch each decade. “And it’s getting faster and faster,” said Bierman. It is likely to be several feet higher by the end of this century, when today’s children are grandparents. And if the release of greenhouse gases—from burning fossil fuels—is not radically reduced, he said, the near complete melting of Greenland’s ice over the next centuries to a few millennia would lead to some 23 feet of sea level rise.
“Look at Boston, New York, Miami, Mumbai or pick your coastal city around the world, and add twenty plus feet of sea level,” said Bierman. “It goes underwater. Don’t buy a beach house.”
Core Assumptions
In 2016, Joerg Schaefer at Columbia University and colleagues tested rock from the bottom of the same 1993 ice core (called GISP2) and published a then-controversial study suggesting that the current Greenland ice sheet could be no more than 1.1 million years old; that there were extended ice-free periods during the Pleistocene (the geological period that began 2.7 million years ago); and that if the ice was melted at the GISP2 site then 90% of the rest of Greenland would be melted also. This was a major step toward overturning the longstanding story that Greenland is an implacable fortress of ice, frozen solid for millions of years.
Then, in 2019, UVM’s Paul Bierman and an international team reexamined another ice core, this one extracted at Camp Century near the coast of Greenland in the 1960s. They were stunned to discover twigs, seeds, and insect parts at the bottom of that core—revealing that the ice there had melted within the last 416,000 years. In other words, the walls of the ice fortress had failed much more recently than had been previously imagined possible.
“Once we made the discovery at Camp Century, we thought, ‘Hey, what’s at the bottom of GISP2?’” said Bierman, a professor in UVM’s Rubenstein School of Environment and Natural Resources and fellow in the Gund Institute for Environment. Though the ice and rock in that core had been studied extensively, “no one’s looked at the 3 inches of till to see if it’s soil and if it contains plant or insect remains,” he said. So he and his colleagues requested a sample from the bottom of the GISP2 core held at the National Science Foundation Ice Core Facility in Lakewood, Colorado.
Now this new study in PNAS, with support from the U.S. National Science Foundation, provides confirmation that the 2016 “fragile Greenland” hypothesis is right. And it deepens the reasons for concern, showing that the island was warm enough, for long enough, that an entire tundra ecosystem, perhaps with stunted trees, established itself where today ice is two miles deep.
“We now have direct evidence that not only was the ice gone, but that plants and insects were living there,” said Bierman. “And that’s unassailable. You don’t have to rely on calculations or models.”
From Flowers
The initial discovery that there was intact biological material—not just gravel and rock—in the bottom of the ice core was made by geoscientist Andrew Christ who completed his PhD working at UVM and was a post-doctoral associate in Bierman’s lab. Then Halley Mastro picked up the case and began to study the material closely.
“It was amazing,” she said. Under the microscope, what had looked like no more than specks floating on the surface of the melted core sample, was, in fact, a window into a tundra landscape. Working with Dorothy Peteet, an expert on macrofossils at the Lamont-Doherty Earth Observatory and co-author on the new study, Mastro was able to identify spores from spikemoss, the bud scale of a young willow, the compound eye of an insect, “and then we found Arctic poppy, just one seed of that,” she said. “That is a tiny flower that’s really good at adapting to the cold.”
But not that good. “It lets us know that Greenland’s ice melted and there was soil,” said Mastro, “because poppies don’t grow on top of miles of ice.”
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Categories: Environment
Re: Greenland fossil discovery reveals increased risk of sea-level catastrophe.
“This new study confirms and extends that a lot of sea-level rise occurred at a time when causes of warming were not especially extreme,” said Richard Alley, a leading climate scientist at Penn State who reviewed the new research, “providing a warning of what damages we might cause if we continue to warm the climate.”
What?? What ‘extreme’ causes of warming did you consider, Mr. Alley? There were no fossil fuels being used a million years ago. There is nothing to indicate that humans were generating inordinate amounts of CO2 a million years ago. And still, the Greenland ice sheet melted. How does that indicate that ‘we continue to warm the climate”? If anything, ‘the discovery’ supports what many have been pointing out for some time now.
Shouldn’t we be paying attention to the big picture? Is CO2 the boogeyman everyone makes it out to be? No. It’s the Milankovitch cycles of the earth’s orbit and the ever-changing tilt of the earth’s axis in relation to the sun. You know, the sun. With radiation cycles we can’t control either.
If we are to be truly ‘careful’ in this regard, we’ll follow the advice of the World Climate Declaration. Don’t invest precious resources trying to mitigate forces beyond our control. Instead, invest in adaptation to those forces. Move above or away from low lying ocean terrain. Move out of flood plains. Repair drainage infrastructure to better control the runoff from the increase in water circulation cycles.
Be smart. Not greedy. After all, it could, just as assuredly, begin to get really cold again too.
“Go for adaptation instead of mitigation; adaptation works whatever the causes are.” – World Climate Declaration
Interesting they decided to “unearth” the previous studies and reexamine the samples to “discover” they confirm what they currently believe about climate change. The funny thing is, the earth is still doing what the earth does, revolving around the sun and producing conditions for life. The conditions may not always be ideal, the dinosaurs didn’t survive, but we still have poppies.
Hopefully we have people with enough intelligence to figure out and act on strategies for adapting. I agree, better to adapt than impoverish people with foolish mandates or manipulating weather with all the associated hazards of messing with complex systems.
Exactly!
I’m all for adaptation too just stop asking Vermonters to buy electric cars, absorb the costs of ever rising electricity, gas, and heating oil when we can’t afford it!!!! We need it to be more affordable here in Vermont. If you want to call out someone—-call out China and India, who do nothing but pollute their air and water and add multiple coal furnaces something like 50 a year. They are laughing at us!!!! Can’t you see this? While you want us to bear the costs of solving the planets woes, they are laughing at us and you care not.
I made a trip from Morrisville area to Chittenden County. Stopped at a service station where lo and behold, they had 4 electric charging stations. How nice and convenient that they built some infrastructure to recharge electric vehicles. However upon closer observation, I saw that all 4 of those charging stations were out of order. Glad that I was not driving an electric vehicle at the time!
This ^
Could this mean the earth’s climate changed without cars, wood burning stoves,petroleum based fuels? Maybe if there had been activists, government agencies, high taxes and punitive regulations for businesses this “climate change” wouldn’t have occurred!! Thank God for all of these policies, taxes/fees and protests that will stop the earth from changing!!!
Lol. Good one
i will not be able to sleep tonight worrying about the sea level/////
Ban geoengineering too. I mean if the coastline is going to disappear why do we need more rain? We certainly don’t need more flooding.
To all UVM globalist scientists/researchers: As a taxpayer funding your Federal grants and other incentives (above and below the lab tables,) any future reports of your “findings” should include the price tag of said “research” and your compensation packages for said “research.” Climate change is the evaperation of real money from many to only a few. They all have a price, apparently, and will do and say anything for a price, plus benefits.
This is solid science that proves that even if the entire ice sheet melts up there, life will survive. This is one of the most optimism-inspiring pieces of climatological news in a while, yet the author uses it as reason to panic. WE ARE STILL HERE, which means we can weather such changes again, if ever they get that severe.
There are former Baltic-Sea ports in Sweden now a hundred miles inland, because even in the last thousand years the climate has shifted so dramatically with the sudden occurrence of the Little Ice Age. This is NOT climate-change denying: this is pointing out that we have gone through worse and ARE STILL HERE.
This is solid science that proves that even if the entire ice sheet melts up there, life will survive. This is one of the most optimism-inspiring pieces of climatological news in a while, yet the author uses it as reason to panic. WE ARE STILL HERE, which means we can weather such changes again, if ever they get that severe.There are former Baltic-Sea ports in Sweden now a hundred miles inland, because even in the last thousand years the climate has shifted so dramatically with the sudden occurrence of the Little Ice Age. This is NOT climate-change denying: this is pointing out that we have gone through worse and ARE STILL HERE.