According to the Guardian, for the first time since scientists began making statistics, the ice sheet of the Arctic Ocean in Siberia has yet to form at the end of October. Climate scientists say this is a warning signal about effects can occur throughout the polar region.
This can be caused by the eerily prolonged warm weather in northern Russia, as well as the intrusion of hot Atlantic currents.
The sea water temperature in this area increased by more than 5 degrees Celsius compared with the annual average, while in winter last year, the ice sheet also melted earlier than previous years.
It takes a long time for this layer of heat to neutralize into the atmosphere, although at this stage of the year the sun appears only two hours a day. The graph of the Laptev sea ice extent shows that this year, the water surface area reached record levels.
“The state of the sea that has not frozen until this fall this year is unprecedented in the Arctic regions of Siberia,” said Zachary Labe, a postdoctoral researcher at the University of Colorado. This is consistent with the projected impacts of climate change, he added.
“2020 is another year when the Arctic is changing rapidly. Without systematically cutting greenhouse gas emissions, it’s likely we’ll see ‘ice-free’ summers in the 21st century,” Mr. Labe said.
Higher air temperatures are not the only factor slowing ice formation. Climate change also causes hot currents of the Atlantic to drift toward the Arctic, and disrupts the usual stratification between warm deep water and cooler surface waters. This also makes it difficult for the ice to form.
Much of the old Arctic ice is disappearing, leaving behind a thinner seasonal layer of ice, said Walt Meier, senior researcher at the US National Snow and Ice Data Center. Overall, the average Arctic ice thickness is only half that of 1980.
The downtrend is likely to continue until the Arctic has its first ice-free summer, Meier said. Simulation data and models suggest this will happen between 2030 and 2050. “It is not a question of whether it will happen or not, but when,” said Meier.
Scientists think the slow formation of the Arctic ice sheet may amplify the rate of thawing. It is widely understood that having less ice means less area for light reflection (as white will reflect light instead of absorbing), and that will cause the area temperature to rise.