Fossils in a Forgotten Ice Core Rewrite Greenland’s Icy Past
Image: NASA
Andrew Christ remembers the day he became part of “this 60-year, weird, wild Cold War story.” It was 2019, and the University of Vermont researcher was just four days away from defending his dissertation. He was beyond stressed and had better things to do than help examine an ice core sample drilled decades earlier.
The core was subglacial sediment and rock, taken from below a mile of ice in 1966 at Camp Century, an American research base in Greenland that had served as cover for a secret—and failed—military project. Since being pulled from beneath the ice sheet, the sample had been separated from the rest of the core, had criss-crossed the Atlantic, was lost, and then rediscovered. But it had never been analyzed.
“Miraculously, it had stayed frozen all that time,” says Christ. “The first thing we did was melt it.” Christ and other geology department colleagues were sorting through sediment from the core sample, washing it off before the next stage of analysis, when he noted peculiar black specks floating in the water. He collected a few and put them under the microscope for a better look. “Oh my God, these are plants,” he remembers exclaiming. “I went full-on mad scientist.”
After his initial giddiness, the significance of the specks sank in. Christ, the lead author on a paper published this month in Proceedings of the National Academy of Sciences, had found in the sediment “freeze-dried fossils” and other direct evidence that Greenland was ice-free in the last million years.
The finding is more than an academic curiosity: It has direct implications for our future. “It’s not if Greenland is melting, but how fast,” says Joerg Schaefer, a coauthor and climate geochemist at Columbia University’s Lamont-Doherty Earth Observatory. Together with a sample from central Greenland that he and colleagues analyzed in 2016, he says, the Camp Century material shows that “there is no question: Greenland is an unstable ice sheet.”
For Schaefer, analyzing the Camp Century subglacial sample after it languished for more than half a century is a thrill, even though his team’s results are bad news. “As a scientist, it’s exciting,” he says. “As a citizen of the planet, it’s horrifying.”
Researchers had long thought that Greenland’s ice sheet, more than 2 miles thick in places, was essentially permanent and had blanketed the island for more than 2 million years. The subglacial sample confirms the massive ice sheet can probably melt far more easily than most models suggest, which would dump enough water into the oceans to raise sea levels by up to 20 feet, all but wiping major cities like London and Boston off the map.
“This study is very important. It shows the Greenland Ice Sheet can disappear with the kind of climate warming we’re projecting over the next century,” says William Colgan, a climatologist for the Geological Survey of Denmark and Greenland who was not involved in the research.
Earth’s polar regions are warming much faster than the rest of the planet, with most models suggesting a rise of at least 40 degrees Fahrenheit (more than 8 degrees Celsius) in the next century. Together with the 2016 analysis, the new Camp Century paper shows that such a temperature bump is enough to melt the ice sheet and cause catastrophic sea rise. “The Greenland Ice Sheet can disappear,” says Colgan. “It is remarkably climate-sensitive.”
The Camp Century sample’s role in rethinking the impact of climate change is just the latest twist in its strange history. In 1959, the American army set up Camp Century in northwestern Greenland, ostensibly for scientific research. The site’s true purpose, however, was Project Iceworm: a secret Cold War plan to build hundreds of miles of tunnels about 25 feet into the ice to store nuclear missiles within striking range of the Soviet Union.
The secret military plan never happened—engineers quickly learned how rapidly and unpredictably the ice can shift, making the site highly unstable and wholly unsuitable for nuclear weapons. Colgan, the project manager for the Camp Century Climate Monitoring Program, is one of a handful of people who have been to the site of the former Army installation, now buried under more than 100 feet of accumulated snow and ice. “The tunnels are collapsed and compressed,” he says. “The snow has turned to ice with pancakes of debris.”
Camp Century was abandoned in 1967, just a year after its engineers managed a true scientific feat: drilling the first ice cores. Together with more recent cores from Antarctica and elsewhere in Greenland, these slim cylinders of ice provide a crucial record of ancient climate conditions that researchers have since used both to understand our past and model our future. Colgan says Camp Century has been invaluable for science, now more than ever.
“Camp Century was the first ice core program, and we’re still learning from it,” Colgan says, adding that the Cold War–era team probably realized the site’s unsuitability as a missile base very early in their work, but persevered in the name of science. The subglacial sample, he says, “only exists because they wouldn’t take no for an answer. They punched all the way into the bedrock and even then kept going.”
Some of the mile-long Camp Century ice core had been previously studied. After being collected in 1966, however, the subglacial core sample—about 12 feet of frozen mud and bedrock from below the ice—was stored in an Army lab freezer, then at the University of Buffalo. The sample was eventually sent to Denmark, where it languished yet again, at the University of Copenhagen’s ice core archive.
In 2017, as staff prepared to upgrade the facility, someone noticed unopened boxes of Camp Century core samples. Inside, rather than the slim cylinders typical of ice cores, they found glass jars of subglacial rock and clumps of frozen sediment. Almost immediately, the find became a sensation in the field. Getting a comparable subglacial sample today using modern drilling technology would have been prohibitively expensive.
“We knew how important these samples would be. All of us started shaking and even drooling a bit,” says Schaefer. As word of the samples spread, he flew to Copenhagen with University of Vermont geologist Paul Bierman in hopes of negotiating for some of the material. “We were trying not to let them see how excited we were. We just tried to keep it together.”
Subglacial material, collected from where the drill hit sediment and bedrock below the ice sheet, contains information the ice does not. Exposed rock, like everything else on Earth’s surface, gets bombarded with cosmic rays, producing chemical signatures, called cosmogenic nuclides, that can be used to establish whether, and when, an area was ice-free. “The nuclides are only produced if the rock sees open sky,” Schaefer says. The work of dating the material is “really, really hard,” says Colgan, but the Camp Century sample has been initially dated, with confidence, as less than a million years old, lining up with the previously studied sample from central Greenland.
Christ, Schaefer, and their colleagues continue to analyze the Camp Century material to narrow its age range and learn more about the plant material it preserved, which is unique, since massive ice deposits usually destroy organic material. The next phase of research, already underway, includes searching for traces of DNA that could be used to determine the species present, and even reconstruct the entire ecosystem.
So far it appears similar to modern Arctic tundra.
There’s yet more to the Camp Century core to explore. The very bottom layers of the sample include sediment that may be up to 3 million years old, Christ says, and may include more organic matter that could be “the oldest material ever recovered from under the ice.”
Camp Century may never have hosted nuclear weapons, but it is proving to be far more significant than even its planners imagined.
See more here: wired.com
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Jerry Krause
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Hi PSI Readers,
Great Article (Story)!!! It explains much but when I read ““Miraculously, it had stayed frozen all that time,” says Christ. “The first thing we did was melt it.” Christ and other geology department colleagues were sorting through sediment from the core sample, washing it off before the next stage of analysis, when he noted peculiar black specks floating in the water. He collected a few and put them under the microscope for a better look. “Oh my God, these are plants,” he remembers exclaiming. “I went full-on mad scientist.” ” I did not immediately understand how the use of a microscope was pessary to see ‘plants’.
So I add (right or wrong) what I did not read in my quick scan of this great article. It would have helped if Christ has accurately definition (describe) the ‘black aspects’ as being preserved parts of plants which had not been totally decomposed by bacteria because of the cold snow which covered them and never melted until the ice core was melted . How many years later we certainly do not know to the nearest century or millennium. (my opinion)
But I add my story to the happenstance that I came to PSI this morning to make a comment to the previous article about this important discovery. For this morning had remembered the phrase–Trial and Error–which I could not have ever read about (only heard about in some long past live discussion.
And I had found: “Trial-and-error meaning
A method of reaching a correct solution or satisfactory result by trying out various means or theories until error is sufficiently reduced or eliminated.
The process of making repeated trials or tests, improving the methods used in the light of errors made, until the right result is found.
The process of finding a solution to a problem by trying many possible solutions and learning from mistakes until a way is found.”
Which I had concluded is now termed TECHNOLOGY or SCIENCE
Have a good day, Jerry
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Terry Shipman
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Shocked? Any good historian could have told them the Vikings colonized Greenland circa 1,000 AD during the Medieval Warm period. Oh, I forgot. The good Dr. Michael Mann disproved the existence of the Medieval Warm Period. Silly me.
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Jerry Krause
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Hi Terry and PSI Readers,
I can back to this article to inform any new readers of another previous article (https://principia-scientific.com/ancient-undergrowth-discovered-beneath-greenlands-ice-sheet/#comments) relative to this discovery. About which MattH had commented: “Hi is there anybody … out there?”
Terry, I must judge your comment implies there is little to no importance to this present article. However, I ask: Was ther a mile thick ice sheet over the land ‘that the Vikings colonized Greenland circa 1,000 AS?
This article proves BETTER LATE THAN NEVER. One cannot argue observed facts. So one must explain how a mile thick ice sheet was formed over the land after a previous melt.
Have a good day, Jerry
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Terry Shipman
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I think recorded history simply proves that Greenland has had a variable temperature record and we should not be surprised that at times it could support human civilization. And we should not attempt to rewrite historical records to satisfy political and scientific agendas.
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Jerry Krause
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Hi Terry,
Did you notice that these scientists are not writing about billions of years. “Researchers had long thought that Greenland’s ice sheet, more than 2 miles thick in places, was essentially permanent and had blanketed the island for more than 2 million years.” And not even millions of years, but only 2 million of years.
““This study is very important. It shows the Greenland Ice Sheet can disappear with the kind of climate warming we’re projecting over the next century,” says William Colgan, a climatologist for the Geological Survey of Denmark and Greenland who was not involved in the research.” And, “Earth’s polar regions are warming much faster than the rest of the planet, with most models suggesting a rise of at least 40 degrees Fahrenheit (more than 8 degrees Celsius) in the next century.”
Here, we see that these researchers, as excited as they are about this new observation, cannot give up their models which before this discovery were predicting that human activity would accelerate the melting of the Greenland Ice sheet, but I had never read this bold of a prediction.
While I have one or more less important comments to make, they are less important to current and future scientific study, so they can wait.
Have a good day, Jerry
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Terry Shipman
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Yes, I knew they were talking about geologic ages past. I knew Greenland had a temperate past. There should have been no surprise at their findings. It confirmed what they should have already known. My point is the alarmists seem to always to use things like this to stoke fears of climate change. The glaciers in Greenland aren’t going away any time soon. And therefore the sea levels aren’t going to inundate us because of it.
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Charles Higley
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““This study is very important. It shows the Greenland Ice Sheet can disappear with the kind of climate warming we’re projecting over the next century,” says William Colgan”
Not so fast. Slow down and think about the realities. At 6 deg F (let alone the 4 mentioned here) warmer temperatures, it would take thousands of years for the ice sheet to melt. If a city cannot handle 20 feet of sea rise in a thousand years, we are dealing with idiots and deserve to drown.
The actual climate warming predicted is based on computer models which have been 100% wrong thus far. Overall, we might have warmed 2 deg F in the last 150 years, but, then, that was the planet emerging from the Little Ice Age. As the planet is doing nothing right now and likely entering a cooling phase, the researcher should be careful about alarmism, which is encouraged by the warmist advocates.
The truth be told, warm phases have always favored human and natural aspects of the planet. And rising CO2, mostly modulated by the oceans, is a boon for plant life in and out of the oceans. There is no down side to CO2, as, when it rises, the absolute humidity decreases, such that the effects of these radiative gases are relatively constant, if not less.
During daylight, radiative gases are saturated with IR radiation, absorbing and radiating at the same time, becoming a wash for the atmospheric energy. However, during night-time, with no external energy input, CO2 and water vapor actively convert heat in the air to IR and radiate them out to space. In fact, these radiative gases serve to cool the planet, which is the exact opposite of the politically biased contention that CO2 is a “greenhouse gas,” a term cobbled up to serve an agenda.
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Doug Harrison
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“A term cobbled up to serve an agenda” But the agenda is much more short term in that these people know that if they can get plenty of alarming statements into their article they will attract bigger and better grants from the governments who have politicised science in the first place.
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Jerry Krause
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Hi Charles and Doug,
It is a historical fact that the ideal known as the greenhouse effect of atmospheric carbon dioxide was proposed by Svante Arrhenius (1896) with the prediction that if not for atmosphere carbon dioxide the measured air temperature would be about 33C less.
Evidently you are not aware that observe data can be used to absolutely refute such a wrong idea. The air temperature has never be measured to the less (lower) than the air’s dew point tiemperature measured at the same place and time. Hence the measured air temperature can never be less than that measured. Which obviously refutes the prediction of the idea of the greenhouse effect.
I have written this several times here at PSI and I have yet to read that you agree that these observed facts are what proves that the GHE is absolutely wrong. You cannot question or argue about these common measurements.
And to criticize these scientists’ about their discovery is wrong behavior. They could have melted the ice and flushed it down the drain. Have you never made a mistake. They have honestly reported an unquestionable observation which they conclude that a more than a mile-thick ice sheet has melted in the past.
But I have being reading about volcanic flow (Physical Geography 3rd Ed,,1969, Athur N. Strahler) and based upon what I have read it seems much of this thick ice sheet slide off the top of Greenland into the ocean surrounding it. That is when it did not snow enough balance the sheet that was sliding off.
Strahler began his chapter about glaciers: “Most of us know ice only as a brittle, crystalline solid because we are accustomed to seeing it only in small quantities . Where a great thickness of ice exists, let us say 200 or 300 ft (16[61?] to 90 m) or more, the ice at the bottom heaves as a plastic material and will slowly flow in such a way as to spread out the mass over a larger area, or to cause it to move downhill, as the case may be.”
Have a good day, Jerry
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