Why Arctic sea ice just crashed to an extreme, record low
Where there should be ice-clad seas, there is vast, open ocean.
Arctic sea ice — declining now for decades — has plummeted to a record-low for this time of year. The oceans above Russia and Siberia have a particularly glaring lack of ice.
"Right now it’s quite extreme," said Walt Meier, a senior research scientist at the National Snow and Ice Data Center..
To appreciate the exceptional loss of ice, take a look at the map below. The orange line shows where ice typically is on July 19. Clearly, the sea ice is vastly diminished.
Sea ice is the lowest on record along the Siberian side of the Arctic, especially in the Laptev Sea, noted Zachary Labe, a climate scientist at Colorado State University's Department of Atmospheric Science. In total, Arctic sea ice is about 500,000 square kilometers (some 193,000 square miles) under the previous record low for this time of year.
"Once again, we are seeing a truly remarkable event within the Arctic Circle," said Labe.
A number of factors stoked the recent Arctic sea ice crash. These factors are largely influenced by the relentlessly warming climate.
An extreme heat wave recently hit the Siberian region, with a Russian town reaching 100.4 degrees Fahrenheit, the highest temperature ever recorded in the Arctic Circle. This heat likely melted sea ice above Siberia, too, explained Meier. Warm temperatures cause water to pool on the surface of sea ice, accelerating melt. "Everything amplifies when you get that heat early in the season," said Meier.
There are now vast regions of open water, which also amplify Arctic heating and ice melt. "Due to the wide open ocean, which would normally still be sea ice-covered, sea surface temperatures are rising more than 5 C (9 F) above average as sunshine (heat) is absorbed into the water," explained Labe. Water temperatures are well above freezing in waters above Siberia, at some 40 F. "That’s really warm for the Arctic," said Meier.
Sea ice was significantly thinner than average this winter, meaning ice melts more easily during the summer.
Winds blowing from the south pushed sea ice away from the usually ice-blanketed coast.
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It's much too early to say if Arctic sea ice overall will fall to a record low extent this year (an event that occurs in September, known as the "sea ice minimum"). Though, it's now starting to look "ominous" said Meier.
Yet, record or not, the big picture is already clear, and becoming clearer:
The Arctic is warming about three times faster than the rest of the world, and the sea ice trend, compared to the historical record, is plummeting sharply.
Less sea ice means a warmer Arctic, and there's mounting evidence that a heating Arctic results in more persistent atmospheric patterns, creating stagnant weather events like longer heat waves in the U.S, Europe, and elsewhere.
Unprecedented fires have erupted in the Arctic Circle over the last two years. A warmer Arctic may mean a shift towards extreme fire behavior in this polar region , burning that releases copious amounts of heat-trapping carbon dioxide into the atmosphere.
The loss of sea ice devastates polar bears, who require sea ice to hunt. Biologists expect many polar bear subpopulations to die out this century.
As the once frozen ground (permafrost) thaws, infrastructure like oil tanks have begun to fail, recently resulting in environmental pollution and devastation.
The extreme ice loss this July is yet more stark evidence of a profoundly changed, and changing, globe.
"Without a large-scale reduction in greenhouse gas emissions, these types of extreme events will become more frequent in the 21st century," said Labe. "2020 is another alarm bell."
Mark was the science editor at Mashable. After working as a ranger with the National Park Service, he started a reporting career after seeing the extraordinary value in educating people about the happenings on Earth, and beyond.
He's descended 2,500 feet into the ocean depths in search of the sixgill shark, ventured into the halls of top R&D laboratories, and interviewed some of the most fascinating scientists in the world.
