Jars of dirt taken from a Cold War military caper and lost in a freezer for decades could hold new essential information about climate change and rising sea levels. A study published Monday in the Proceedings of the National Academy of Scientists says plant fossils found in a specimen of dirt collected from a mile under ice in the mid-1960s suggest that the world’s prehuman climate was once warm enough to to completely melt the ice sheet of Greenland.
The soiled inspectors inspected are a sample of sediment from the bottom of an ice core, recovered by drilling in the ice sheet that covers most of Greenland. It’s quite difficult to actually get to the bedrock when you take samples because of the incredible pressure from the ice, explained Drew Christ, lead author of the study and a postdoctoral fellow at the University of Vermont. There are only a few expeditions that actually obtained sediment from the bottom of the glacier. “It simply came to our notice then [sediment] than the rocks of the moon, ”Christ said.
This sample produced a lot of plant matter, some of which was visible to the naked eye. “It’s like hiking and having a bunch of twigs and flooring in the bottom of your boot and pouring them at the end of the day,” Christ said. “It’s kind of like that, but it’s been frozen for 1 million years.”
Christ and the team behind the study used isotopic analyzes of various elements that helped the researchers remove the last time the evidence was exposed to the sun and cosmic rays. The dating showed that the plant matter is about 1 million years old.
G / O Media may receive a commission
Before analyzing this particular sample, Christ said, scientists had “circumstantial” evidence that the Greenland ice sheet had once completely melted. But the discovery of these fossils definitely suggests that Greenland was once ice-free enough to provide a home for a variety of plants. And that’s bad news for us right now. Greenland’s ice sheet is a ticking climate bomb, with some estimates that the sheet could rise by 6.1 meters. if completely melted. Although it is not scheduled to melt completely tomorrow, the ice sheet is now melting six times faster than it was in the 1980s. The changes triggered by rising carbon dioxide will take centuries to unfold as the climate adjusts to a new equilibrium. Knowing its history is crucial to understanding the future of the ice sheet.
“The Greenland ice sheet has disappeared into a climate system that has had no human influence,” Christ explained. “Before humans added hundreds of parts per million fossil fuels to the atmosphere, our climate managed to melt the ice cap. In the future, as we continue to warm the planet at an uncontrollable rate, we could force the Greenland ice cap to cross a threshold and melt it and raise sea levels. ”
The specimen of dirt that Christ and his team used to reach these conclusions has its own incredible history, including the fact that it was almost lost in history. The sample was originally recovered from the first ice core in Greenland ever taken during a 1966 expedition to a military base called Camp Century. The real purpose of the expedition was a top secret James Bond mission called Iceworm project (yes, indeed) to try to hide the nuclear missiles under the ice near the Soviet Union (we don’t invent that). The scientific part of the expedition, although valid, was created mainly to cover this caper of the Cold War. The Iceworm project eventually failed, but at least I got this fascinating ice core out of it. (The disadvantage is that climate change is melting in the century of the Camp and could causes a discharge of toxic waste from cold war supplies and chemicals.)
Although the dirt sample itself is remarkable, as the Camp Century test was the first ice core ever recovered from Greenland, researchers were largely interested in what the ice itself might call them and invested less in the dirt. which came with the core.
“I used to pull centimeter-long twigs out of these things. We could see with our own eyes as if it is definitely plant material “, said Christ. “Looking at this as someone who was born after subtracting any of these, it’s like he did [the scientists] don’t you think to look more closely? I think they had more priority to analyze the ice and then the soil was not analyzed. “
In what Christ describes as a “strange trick of history,” soil was such a low priority for researchers that it was finally lost when the expedition arrived home. The samples were placed behind an army freezer at the University of Buffalo, then moved incognito with a pile of other materials into another freezer at a research unit in Denmark in the 1990s. Only in 2017, while JP Steffensen, one of Christ’s mentors and author on paper, was making an inventory, helping that facility prepare its freezer for a move, the evidence was rediscovered and could be analyzed more fully.
And even though researchers in the 1960s did not know what they got when they dug up the old dirt, Christ is grateful that their work gave him one of the most exciting moments of his scientific career.
“The day I found the fossils was one of those ‘eureka’ moments. I never thought those days were actually happening to scientists, but it happened to me, ”he said, describing how he first saw stains of plant material as his team cleaned up sediment samples for analysis. “I was jumping in the lab. It was so interesting. ”