By Allison Kubo
New research published in the Proceedings of the National Academy of Sciences shows that in the last 1.1 Ma the Greenland Ice sheet melted at least once and reformed. The team found fossilized plants buried under 1 million years of snow based on the Camp Century Ice Core. The long core samples the layers of snow in the Greenland Ice Sheet.
|Silvan Leinss, Radar reflector installation Greenland, CC BY-SA 4.0|
The deeper the core the older the ice is and at its deepest point the Greenland Ice Sheet measures approximately 1.9 miles. Finding dirt and plant material in the core under layers of ice indicates it was once covered with plants and maybe even trees. The researchers used cosmogenic isotopes, atoms that are only formed when radiation from space and the sun interact with dirt, to show that it melted at least once within the last 1 million years. Although it may seem like a long time, 1 million years is an eyeblink to geologists. This research indicates that Greenland could almost completely melt and refreeze in a very short timescale. It highlights that climate change is a threat to humans in our lifetimes and that the Greenland Ice Sheet is very sensitive to climate changes.
|Photo Credit: Aussie55|
This isn’t the first time that the Camp Century Ice Core has had important scientific or even societal discoveries. The saga took to get this research includes secret cold war missions, abandoned bases, modular nuclear reactors, lost data, and a 4560-foot sample of the Earth’s past.
Drilled from 1963-1966, it was one of the first long ice cores to be used to model climate and look at Earth history. Camp Century, only 800 miles from the North Pole, was built into the ice including barracks, a theater, and a barbershop, all powered by a portable nuclear reactor. But climate science at Camp Century also hid more troubling motives. Camp Century was the home of Project Iceworm, declassified in 1996, which was a mission to station 600 nuclear warheads under the ice. They soon learned the ice was too unstable to maintain the base let alone launch missiles. The US Army abandoned the base and their waste to be reclaimed by the ice. Although originally intended as a cover, the ice core became the subject of major work in climate research, climatology, even volcanology since it recorded ash from large eruptions. However, as new cores were drilled the interest in Camp Century decreased and it was shipped around from New Hampshire to Buffalo and eventually to Copenhagen in the 1990s. The boxes and boxes of ice were forgotten in the freezer in Denmark until 2018. We continue to see the legacy of the Camp Century ice core with the recent research published by the University of Vermont.