After reaching the second-lowest extent ever recorded last month, sea ice in the Arctic has begun to refreeze in the face of autumn temperatures, closing both the Northern Sea Route and the direct route through the Northwest Passage.
© ESAParry Channel in the Canadian Arctic Archipelago, as seen by Envisat's ASAR on 25 August 2008, when the direct Northwest Passage was open (right image), and on 22 September 2008 when sea ice is closing the direct Northwest Passage.
This year marked the first time since satellite measurements began in the 1970s that the Northern Sea Route, also known as the Northeast Passage, and the Northwest Passage were both open at the same time for a few weeks.
"NIC analysis of ESA's Envisat and other satellite datasets indicated that the Northern Sea Route opened when a path through the Vilkitski Strait finally cleared by 5 September," NIC Chief Scientist Dr Pablo Clemente-Colón said via email from aboard the US Coast Guard icebreaker Healy in the Arctic, where he is conducting joint mapping operations with the Canadian Coast Guard.
"This is the first time in our charting records that both historic passages opened up in the same year," Clemente-Colón said. "Both of the routes appeared as closed by 22 September."