Greenland without ice and snow? Scientists reveal shocking facts about the Arctic's past

Scientists from the University of Innsbruck (Austria), led by geologists Gina Moseley, Gabriella Koltai and Jonathan Baker, have discovered sediments in Cove Cave that prove that millions of years ago the region was significantly warmer and free of permafrost.

The study, published in Nature Geoscience, sheds light on the climate of the late Miocene (about 11-5 million years ago), a period when carbon dioxide levels and atmospheric temperatures were similar to those predicted for the coming decades.

Cove Cave is located in one of the most inaccessible corners of the Earth, on the north coast of Greenland. It can only be reached by small aeroplane and then on foot through wild, uninhabited areas. Inside the cave, scientists discovered calcite deposits that can only form at positive temperatures and in the presence of running water. This provided crucial evidence that in the past there was no permafrost here and the climate was much wetter.

"These sediments are like tiny time machines," Moseley says. - They prove that northern Greenland was once warm and ice-free."

The analyses show that between 9.5 and 5.3 million years ago, there were at least several phases of warm and wet climate in northern Greenland. The average annual temperature during those periods was about 14°C higher than today, and CO₂ levels in the atmosphere exceeded 310 ppm. Between warm phases, the climate cooled and small glaciers formed.

This shows that the Arctic is highly sensitive to changes in external conditions. "This is the first time we have such a detailed 'land' climate archive from the High Arctic, and it matches the marine data strikingly closely," notes Moseley.

Against the backdrop of modern warming, the data from Greenland's caves become particularly significant. Already today, CO₂ concentrations exceed the levels at which permafrost thawed in the late Miocene. And these permafrost soils contain gigantic stores of carbon that can be released as methane and carbon dioxide, amplifying the greenhouse effect.

"The Arctic is not a stable system. It can change very rapidly," Moseley emphasises. - "Every tenth of a degree matters. And every step to reduce emissions is important to avoid dangerous feedbacks."