Arctic Sea Ice Fails to Refreeze by Late October, Setting a New Record - Smithsonian Magazine

sea.indah.link

With winter just around the corner, the Laptev Sea in the Arctic Circle should be starting to form thick sheets of sea ice as temperatures in the Northern Hemisphere plunge. But the seascape looks drastically different this year—it's already late October, and the Laptev Sea still hasn't refrozen, setting a new record for the latest delay in ice formation the sea has ever experienced, reports Jonathan Watts for The Guardian.

The Laptev Sea, located on the northwest coast of Siberia, is the Arctic Ocean's main sea ice nursery. Strong offshore winds accelerate ice formation, then, the wind circulates the ice across the Arctic, supplying the ocean with floating ice packs. However, a heat wave in the Arctic this summer caused the ice to melt more rapidly than usual, leaving the open water exposed to the sun for longer, reports Dharna Noor for Gizmodo.

"With these newly open waters, direct sunshine was able to warm up the ocean temperatures to more than 5 degrees Celsius above average," Zachary Labe, a climate scientist at Colorado State University, tells Gizmodo in an email. "These warmer ocean waters are slowing the refreeze in the Siberian Arctic now in October."

“Since this year is observing such a late refreeze in the Laptev Sea, any sea ice that forms later this fall and winter will not have as much time to thicken,” Labe tells Gizmodo. “Younger and thinner ice is more vulnerable for melting during the summer, which means it could again disappear earlier than usual, leaving large pools of open water which absorb even more heat.”

For the Laptev Sea, a shortened period to build ice sheets could mean that by the time the ice floats to other regions of the Arctic, it may already melt.

#Arctic sea ice extent is currently the lowest on record for the date. The amount of open water this fall is absurd.

Compared to previous decades:
---> about 1,680,000 km² less the 2010s average
---> about 4,050,000 km² less the 1980s average pic.twitter.com/42X4ou3wO0

— Zack Labe (@ZLabe) October 22, 2020

According to the National Oceanic and Atmospheric Administration, Arctic sea ice is on track to reach an all-time low in recorded history. And as climate change intensifies, scientists say that we'll see an ice-free Arctic summer within the next few decades, which hasn’t happened in tens of thousands of years, reports Becky Ferreira for Vice.

An ice-free summer is "a matter of when, not if," Walt Meier, senior research scientist at the U.S. National Snow and Ice Data Center, tells The Guardian. He says that 2007 to 2020 resulted in the 14 lowest ice years in recorded history. For perspective, ice sheets were twice as thick in the 1980s than they are now, he says. Satellite records show a 13 percent decrease in sea ice per decade since the 1980s.

Shrinking ice sheets leave less snow-covered surface area to reflect sunlight away from the Earth's surface. Smaller ice sheets mean larger swaths of open ocean, which absorb heat, warming the temperature of the sea. This feedback loop could lead to an ice-free summer by 2035, reports Gizmodo.

"We are currently in uncharted waters with record low Arctic sea ice this late in the year," Geoff York, senior director of conservation at Polar Bears International, tells Gizmodo in an email. "This is yet another red flag from our rapidly warming planet—trying to warn us of changes yet to come."

The Link Lonk


October 27, 2020 at 02:26AM
https://ift.tt/34t5Xhw

Arctic Sea Ice Fails to Refreeze by Late October, Setting a New Record - Smithsonian Magazine

https://ift.tt/2CoSmg4
Sea