Eastern greenland melting ice ▶ Click here for a larger view
Research shows 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 m.
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.
◇Plant traces found under 1.38km ice in Greenland
Plant traces in sediments under Greenland ice ▶ Click here for a larger view
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 analyzing sediment samples under the 1.38km ice sheet of the US military base in the Arctic Circle in the northwest of Greenland in the latest issue of the National Academy of Sciences (PNAS). did.
The team used a microscope to find twigs and leaves in the 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.” did.
The research team measured the ratio of beryllium and aluminum isotopes in the rock that is not covered by ice, but formed only when exposed to the surface and subjected to cosmic rays, and whether it is covered with an ice sheet through the form of oxygen found in the ice in the sediment. Analyzed.
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 a temperature rise called an interglacial period. However, this relied solely on indirect evidence, such as coastal drilling or rocks 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 failed nuclear missile secret base and the sample that reappeared dramatically
‘City under the Ice’ Camp Century The samples used in this study were taken by scientists when the US military built Camp Century under the 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 nose of the former 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 risk of collapse was raised by the weight of the snow, and the base construction under the ice ended in failure.
At the time, scientists drilled up to 1.38 km at Camp Century to secure an ice core, but focused only on the ice samples containing the history of the ice sheet and did not pay attention to the sediments under the ice sheet collected by digging about 3.6 m further.
The sediment samples were eventually transferred from the U.S. Army Research Institute freezer to the University of Buffalo and then to the University of Copenhagen, Denmark in the 1990s, but lost in a corner. 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” was accidentally discovered and came to light.
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