A 10,000-square-kilometer piece of ice like Hawaii vanished in the blink of an eye 11,000 years ago from a layer that covered the sea. Off the coast of Svalbard, In the arctic.
According to a new study, this dramatic event was preceded by a fairly rapid melting of 2.5 kilometers of ice annually. This parallels Current melting rates in Antarctica and Greenland Scientists are concerned behind the study.
Measurements of glacial retreat in the Storfjorden Basin (the Arctic Sea region where the study was conducted) show that conditions prevailing up to the 11,000-year-old event match what we see in Antarctica and Greenland today. “Amazing thing. There are new studies published almost weekly, showing that the current ice sheet retreat is 2 to 4 kilometers per year and this is accelerating, “said the professor at the Arctic Gas Hydrate Center, the Environment and Climate and first author, Tyne Lander Rasmussen.
Melting of ice in the Arctic Ocean, linked to climate change. Photo: EFE
Last melting, 20,000 to 10,000 years agoIt was a period of global warming coexisting with rapid shrinking of the ice sheets. But stating the actual relationship between the two is not as simple as it sounds. The period in question was climatically unstable, and the main thaw was interrupted by re-freezing and the formation of new ice. Therefore, it was difficult to determine the speed of the ice retreat, in relation to climate change.
“We studied the evolution of the ice sheet 20,000 / 10,000 years ago using Cores marine sediments. Twelve nuclei have been collected in the region over the past 18 years and have been carefully analyzed for different types of micro-fossils of a single-celled organism called foraminifera, “Rasmussen says.
The biochemistry of fossil foraminifera helps reconstruct the vast amount of information about the state of the environment in prehistoric times. The sediments were chopped up It represents time periods from 30 to 70 years. Over 70 samples have been dated and analyzed.
“What we saw is that the ice sheet began to retreat about 20,000 years ago, but it remains on a ridge in the strait. Then, about 15,000 years ago, the atmosphere and oceans have warmed, affecting ocean circulation. A large portion of the cover disappears. Glacier at the same time, at the beginning of the warm Holocene period, 11,000 years ago things really speeded up. We cannot see any other evidence of the ice sheet that covered the ocean floor after that time. “
Map of the Greenland ice sheet location and extent in 2008 estimate for 2300.
Periods of extremely rapid retreat of the ice sheet are constantly associated Periods of global warming of the oceans And temperature. This is reflected in the retreat of ice cover from eight other strait systems in northern Norway.
“This reinforces our hypothesis that ocean warming and global warming are the direct causes of the chain of events that led to the rapid disintegration of the ice sheet,” Rasmussen says. This gives some Disturbing views on the current landscape. The great thaw from the greatest glaciers to the Holocene took 10,000 years to prepare. Climate change today is much faster.
“ The final retreat of the ice sheet Storfjorden Trough It happened quickly in the outer parts as it did elsewhere in the Depression. This means that once warmer ocean water reached the ice sheet, it rose rapidly inland from the edge of the ice shelf. Within the class itself. We see this happening in Antarctica today. Larsen’s separators A (1995), B (2003) and C (2017) are examples of this process. “