Studies have shown that the ice covering Greenland near the Arctic Ocean has completely or almost completely melted at least once in the past 1 million years.
This suggests that the ice that covers 85% of Greenland, the world’s largest island, can melt much more easily than ever thought, causing countless cities to submerge.
Greenland ice can raise sea levels by about 6 meters.
In particular, these results are also of interest as revealed by samples of ice cores that were discovered after decades of neglect after the US military built a secret nuclear missile base under the Greenland glacier targeting the former Soviet Union in the 1960s.
According to the University of Vermont, an international research team led by Dr. Drew Christ of the University’s Department of Geography announced the results of the analysis of sediment samples under the 1.38 km ice sheet of the US military base’Camp Century’ in the Arctic Circle in northwest Greenland in the latest issue of the National Academy of Sciences Newsletter (PNAS). I did.
The team used a microscope to find twigs and leaves in this sediment sample.
“The ice sheet dusts and destroys anything in its path,” Dr. Christ said. “What we found was a delicate plant structure perfectly preserved,” said Dr. Christ. “A time capsule showing what lived in the past in Greenland.” I did.
The research team measured the ratio of beryllium and aluminum isotopes in the rock that was not covered by ice, but formed only when exposed to the surface and subjected to spacecraft, and analyzed whether it was covered with ice sheets through the form of oxygen found in the ice in the sediment.
As a result, in the last million years, most, if not all of Greenland, have melted at least once to form a green area covered with moss or even fir trees.
Over the past 2.6 million years, Greenland ice has been believed to have persisted during the rising temperatures called interglacial periods.
However, it relied solely on indirect evidence, such as coastal drilling or rock and mud pushed to the shore.
The Camp Century samples were collected 120 km from the coast to the inside of the island and about 1,280 km from the North Pole, and are in line with the analysis data of ice cores collected from two central Greenland locations in the 1990s.
The results of this study are strong evidence that Greenland is more susceptible and more sensitive to climate change than previously thought, confirming that Greenland’s ice can be completely melted during rising temperatures, such as human-induced climate change. It was pointed out that it was to be done.
The samples used in this study were taken by scientists when the US military built Camp Century under an ice sheet in Danish Greenland in the early 1960s.
The US military called Camp Century a’city under ice’ and claimed to be a science base, but in reality, under the name of’Project Iceworm’, the U.S. military drilled 21 tunnels with a total length of more than 3,000 km and opened 600 nuclear weapons in front of the Soviet Union The purpose was to hide the missile.
However, as the ice sheet moved faster than expected, the shape of the tunnel was distorted, and the weight of snow raised the risk of collapse, and the construction of the base under the ice ended in failure.
At the time, scientists drilled up to 1.38 km at Camp Century to secure the ice core, but focused only on the ice samples containing the history of the ice sheet and did not pay attention to the sediment under the ice sheet collected by digging about 3.6 m further.
This sediment sample was eventually transferred from the U.S. Army Research Institute freezer to the University of Buffalo to the University of Copenhagen, Denmark in the 1990s, but was buried in a corner and forgotten.
Then, in 2017, in the process of arranging ice core samples to be transferred to a new freezer, it was accidentally discovered that the label “Sample under the Camp Century Ice” came to light.
(Photo = Courtesy of Joshua Brown/UVM, Yonhap News)