Just a decade ago, global warming was not something that was laughed at, rather not taken seriously, but films like The Day After Tomorrow, perhaps, laid some ground for concern. By the way, you and I really have something to fear: as the results of a new study have shown, one of the so-called "points of no return" seems to have already been passed. The turning point, researchers call the disappearance of sea ice in the Arctic - the world's largest expedition to the North Pole, with the participation of 300 scientists from 20 countries, spent 389 days drifting through the Arctic. Scientists have brought home devastating evidence of the dying Arctic Ocean and warnings that the area will be ice-free in just a few decades. The € 140 million ($ 165 million) expedition also brought in 150 terabytes of data and over 1,000 ice samples. Summing up their first conclusions, the authors of the scientific work noted that the Arctic sea ice retreated "faster in the spring of 2020 than in the entire history of observations."
What is Arctic Gain?
Over the past 30 years, the Arctic has warmed about twice as fast as the entire globe. Researchers call this phenomenon the Arctic gain. Most scientists agree that such rapid warming is a signal of anthropogenic climate change. Arctic gains, however, are not the only evidence of rapid climate change in the Arctic.
The floating sea ice sheet of the Arctic Ocean is shrinking, especially in summer. Snow cover on land in the Arctic has decreased, especially in spring, and glaciers in Alaska, Greenland and northern Canada are also retreating. In addition, frozen soil in the Arctic - permafrost - is also warming up and thawing in many areas. Scientists first began to see evidence of changes in the Arctic climate in the 1980s. Since then, the changes have become much more noticeable. I talked about how the permafrost melting threatens the world in this article.
Melting permafrost has the potential to worsen the effects of climate change.
Arctic sea ice has shrunk to its lowest level on record since September 2012 at 3.39 million square kilometers, according to NSIBC. Changes in the Arctic climate are important, as the Arctic is essentially a kind of refrigerator for the planet, helping it cool down. Thus, changes in the Arctic climate could affect the climate in the rest of the world, cascading the food chain - from phytoplankton to marine mammals such as seals, walruses, whales and polar bears.
Changes in the Arctic are alarming as they could backfire, which in turn could lead to further warming. For example, when white sea ice melts in summer, areas of dark, open water are exposed that can absorb more heat from the sun. This extra heat helps to melt even more ice. The loss of sea ice is known to be one of the driving forces behind the Arctic gain.
Permafrost can also be involved in feedback loops. As it melts, plants and animals that have been frozen in the ground begin to decompose. When they decay, they release carbon dioxide and methane back into the atmosphere, which can contribute to further warming.
Melting Arctic ice will exacerbate an already rapid climate change.
Changes in Arctic vegetation also affect surface brightness, which then influences warming. As the arctic atmosphere warms up, it can retain more water vapor, which is an important greenhouse gas.
What did the results of the Arctic expedition show?
According to The Conversation, new research suggests the payback for inaction on climate change could come much sooner than most people realize.
The results of the expedition showed that the thickness of the ice was only half that, and the temperature was measured 10 degrees higher than during the expedition of Fram - undertaken by researchers and scientists Fridtjof Nansen and Hjalmar Johansen in the 1890s. Because of the smaller sea ice surface, the ocean was able to absorb more heat in the summer, which in turn meant that the ice sheet formed more slowly than usual in the fall.
By the end of the 21st century, the Arctic may change beyond recognition. However, like our planet.
The Arctic is losing ice as global temperatures rise, and this directly affects human lives and triggers feedback loops that fuel even greater warming. But another cause of sea level rise is Antarctica, which contains enough land ice to raise global sea level by more than 60 meters - about 10 times that of the Greenland ice sheet. And scientists are already seeing signs of problems today.
The new study shows that if the amount of harmful emissions into the atmosphere does not change, then by about 2060 the Antarctic ice sheet will cross a critical threshold and lead the world to sea level rise that is not reversible in human time.
Antarctica has several protective ice shelves that fan out into the ocean. When ice shelves collapse, it can expose towering ice cliffs that may not be able to stand on their own. Portions of the Antarctic ice sheet sit below sea level on rock formations that slope inward towards the center of the continent, so warming ocean water can corrode their lower edges, destabilizing them and causing them to retreat quickly downslope. Over water, melting surfaces and rain can open cracks in the ice.
“When ice rocks get too high to support themselves, they can catastrophically collapse, accelerating the speed of ice flow into the ocean,” the authors of the scientific paper write.
The illustration shows how warming water can penetrate and destabilize glaciers
Warmer circumpolar deep water can penetrate under the ice shelves and corrode the base of the glaciers.
Other projections do not account for the instability of ice rocks and tend to give lower estimates of the rate of sea level rise. While much of the press coverage following the release of the new document has focused on the differences between the two approaches, they both arrive at the same fundamental conclusions: the magnitude of sea-level rise can be drastically reduced by meeting the Paris Agreement goals, and physical instability in the Antarctic ice sheet could lead to a rapid acceleration in sea level rise.