The Greenland Ice Sheet is the second largest on Earth after the Antarctic Ice Sheet and covers 1.5 million square meters, with ice depths reaching 3,000 meters
Information about the discovery of an impact crater under the ice of Greenland was published back in 2018. The discovery sparked a lively debate about when the two-kilometer-wide asteroid hit Earth before or after the formation of the Greenland Ice Shell, and scientists have finally put an end to the debate. The Greenland ice sheet formed about 2.6 million years ago. Scientists have found that the 31-kilometer-wide Greenland impact crater Hiawatha was formed during the Pleistocene era, between 11,700 and 2.6 million years ago. The asteroid impact thought to have created Hiawatha Crater would have produced so much heat that the ice sheet would have released a huge volume of meltwater “virtually instantly,” said planetary scientist Elizabeth Silber.
Remains of vegetation were discovered in the northwestern region of Greenland. Scientists conducted a study in which they took soil samples under a layer of ice 2 kilometers thick. The researchers expected to obtain rocks and sand from the prehistoric period. However, it turned out that there was vegetation in place of the glaciers a million years ago. Among the samples obtained, scientists obtained remains of moss, branches and leaves. Experts suggested that the discovered remnants of vegetation are characteristic of the tundra, which covers the part of Greenland that is free from ice. In addition, on the site of glaciers there were once streams and ponds.
New research results were also obtained due to the gradual melting of the Greenland ice sheet. Rising global temperatures are melting Greenland’s ice and glaciers and causing sea levels to rise. New modeling by researchers at the Alfred Wegener Institute in Germany shows a significant difference of several thousand years between high-temperature climates and melting. The researchers said that although the industrial age had caused the Greenland ice sheet to begin losing mass since the 1980s.
Data from the Jakobshavn catchment of the Central West Greenland Ice Sheet shows that this part of the ice sheet has reached a tipping point. This conclusion was reached by Niklas Boers from the Potsdam Institute and Martin Rypdal from the Arctic University of Norway after careful studies of the dynamics of melting rates and changes in the height of the ice sheet over the past 140 years. In the paper, Rypdal and Boers analyzed reconstructions of changes in the height of the Central and Western Greenland ice sheet since 1880 and compared them with corresponding model calculations. Based on their analysis, they concluded that this part of the Greenland ice sheet is losing stability, which is consistent with the idea that it is very close to entering a state of accelerated melting, regardless of whether the warming trend in the Arctic stops in the coming decades.
A positive feedback mechanism is triggered: as the surface of the ice sheet sinks, it is exposed to higher average temperatures, resulting in more melting, further decrease in height, and correspondingly accelerated mass loss. Beyond a critical threshold, this process cannot be reversed because, with decreasing altitude, a much colder climate would be required for the ice sheet to return to its original size.
If the Greenland ice sheet as a whole goes into accelerated melting mode, it will have serious consequences for the entire planet. The Greenland ice sheet contains a mass equivalent to a 7 meter rise in global sea levels. Loss of the Greenland ice sheet is also expected to exacerbate global warming by reducing albedo, as well as disrupting major ocean currents, monsoon belts, rainforests, wind systems and precipitation patterns.