Arctic Sea Routes Stay Open Longer as Militaries Race North

Photo: The Canadian Coast Guard icebreaker Louis S. St-Laurent and U.S. Coast Guard Cutter Healy in the Arctic Ocean (file photo). Photo: Petty Officer 3rd Class Patrick Kelley, U.S. Coast Guard, via Wikimedia Commons, public domain.

The window when ships can sail the Arctic sea routes is getting longer, and the region’s militaries are moving in behind the cargo ships. Satellite records show the Arctic melt season has grown by roughly five days per decade since 1979. In 2025, Russia’s Northern Sea Route logged a record 103 full transit voyages over a season that ran from June 30 to Nov. 17. At the same time, the United States, Canada, the Nordic NATO members, Russia and China are all adding ships, bases and patrols in the far north.

The issue is on the table in Atlanta today. The U.S. State Department said Secretary of State Marco Rubio, South Korean Foreign Minister Cho Hyun and Japanese Foreign Minister Toshimitsu Motegi were scheduled to sign a memorandum of cooperation on a trilateral Arctic-Pacific Partnership at 5:10 p.m. ET Friday, on the sidelines of the G20 foreign ministers’ meeting, Yonhap reported. Seoul officials said possible areas of cooperation include Arctic shipping, maritime safety, shipbuilding technology and energy. Follow the meeting in our G20 Atlanta live updates.

How much longer the Arctic shipping season has become

The core measure is sea ice. A study of passive-microwave satellite data found the Arctic-wide melt season lengthened by about 5 days per decade from 1979 to 2013, according to the 2014 paper in Geophysical Research Letters. The change came mostly from later autumn freeze-up. In the Kara, Laptev, East Siberian, Chukchi and Beaufort seas, which line the Northern Sea Route and the approach to the Northwest Passage, the trend was 6 to 11 days per decade. The authors wrote that this added up to a melt season between one and two months longer over the record in the seas with the largest ice losses.

A separate satellite analysis of 1979 to 2017 data found ice-free periods across the Arctic growing at nearly 12 days per decade, with ice opening earlier and closing later each year, according to the study in Remote Sensing. The researchers noted that results depend on how regions are averaged.

The 2026 season shows the year-to-year swings. The National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder said Arctic sea ice hit its 2026 minimum of 4.60 million square kilometers on Sept. 12. That ties 2008, 2010 and 2025 for tenth lowest in the satellite record. The 20 lowest minimums on record have all come in the past 20 years, 2007 through 2026. In early October the center said the Northern Sea Route “appears to be largely free of ice,” while heavy ice still blocked M’Clure Strait at the west end of the Northwest Passage’s deepwater route and significant ice remained on the southern Amundsen route, according to its October analysis.

What the data shows

The Boston Report’s analysis of NSIDC’s September averages shows ice extent fell from 7.05 million square kilometers in 1979 to 4.81 million in 2026, a drop of about 32%. A straight-line fit to all 48 years gives a loss of about 0.74 million square kilometers per decade, roughly 11.6% of the 1981 to 2010 September average (6.41 million) every ten years. These are TBR calculations from NSIDC data. The lowest September average was 2012, at 3.57 million square kilometers.

Traffic has climbed too, though unevenly. The Centre for High North Logistics (CHNL) at Nord University in Norway, which tracks ships by AIS data, counted 103 Northern Sea Route transits by 88 vessels in 2025, up about 6.2% from 97 in 2024, according to its 2025 season summary. That is more than double the 41 transits in 2011, the first year in the Marine Policy review of CHNL data. CHNL also counted 85 transits in 2021, then 43 in 2022 after Russia’s full-scale invasion of Ukraine, before the recovery to 79 in 2023. A peer-reviewed review of CHNL data in Marine Policy found transits peaked at 71 in 2013 before dropping to 18 in 2015 and 2016.

Rosatom, the Russian state nuclear corporation that runs the route, put 2025 transit cargo at 3.2 million tons, a figure CHNL said its own estimates closely match. CHNL’s 2024 report said the transit trade has become mostly a Russia-China corridor, with no international transits in 2023 or 2024.

Projections: A study in Environmental Research Letters that combined satellite data with climate models projected the Northern Sea Route’s transit window would reach about four months by the end of the century under a moderate emissions scenario, and about six and a half months under a high-emissions scenario. The authors said the observed growth rate may slow over the next few decades. These are model projections, not forecasts for any single year.

Russia: the biggest Arctic military and icebreaker fleet

Russia has adopted a series of Arctic strategy documents since 2008. It has reactivated and modernized Cold War-era Arctic bases, assigned upgraded forces to them and increased its exercises, according to the Congressional Research Service (CRS) report “Changes in the Arctic”. CRS also notes that some analysts argue Russia’s Arctic buildup has been exaggerated or is largely the normal replacement of aging equipment. As of 2019-2020, 80% of Russia’s natural gas and 17% of its oil were produced in its Arctic, the report says.

On icebreakers, the gap is wide. A U.S. Coast Guard count compiled by CRS in its icebreaker report listed 51 major polar icebreakers for Russia as of April 2022, plus two unavailable, against five for the United States, 12 for Canada, nine for Finland and four for China. CRS says the size of Russia’s fleet partly reflects its long Arctic coastline and the roughly 2 million people living in its Arctic.

The United States: icebreakers years behind schedule

The Pentagon’s 2024 Arctic Strategy, its first update since 2019, describes a “monitor-and-respond” approach. Its three priorities are better Arctic capabilities, especially communications and surveillance; work with allies and partners; and a tailored presence through exercises and routine operations.

The Coast Guard has three working polar icebreakers: the heavy icebreaker Polar Star, which entered service in 1976, and the medium icebreakers Healy and Storis, a converted commercial ship that joined the fleet in 2025. A 2023 Coast Guard study said the service needs eight to nine. The first new heavy Polar Security Cutter, originally due in 2024, is now projected for no earlier than 2030, CRS reported in January. On Dec. 26, 2025, the Coast Guard awarded contracts for up to six medium Arctic Security Cutters, two from Rauma Marine Constructions in Finland, with the first due in 2028, and four from Bollinger Shipyards in Louisiana, with the first due in 2029.

Those ships come out of the ICE Pact, a polar icebreaker partnership that U.S., Canadian and Finnish leaders announced on July 11, 2024. Officials signed a memorandum to carry it out on Nov. 13, 2024. In October 2025, the United States and Finland signed a memorandum on procuring up to 11 Arctic Security Cutters, CRS reported.

China and Russia near Alaska

China called itself a “near-Arctic state” in a January 2018 white paper that labeled trans-Arctic shipping lanes a “Polar Silk Road,” CRS notes. China operates the research icebreakers Xue Long and Xue Long 2, and a third, Ji Di, reportedly entered service in June 2024.

On Sept. 28, 2024, a Coast Guard HC-130J from Kodiak spotted two Russian Border Guard ships and two Chinese Coast Guard ships on a joint patrol in the Bering Sea, about five miles inside Russia’s exclusive economic zone. It was the farthest north the Coast Guard had observed Chinese Coast Guard vessels, the service said. “This recent activity demonstrates the increased interest in the Arctic by our strategic competitors,” said Rear Adm. Megan Dean, then commander of the 17th Coast Guard District. In July 2024, Russian and Chinese bombers reportedly operated together near Alaska, CRS said. In August 2025, the Coast Guard said it was monitoring five Chinese research vessels in or near the U.S. Arctic and called it part of a three-year trend.

NATO’s new Nordic flank, Canada and Greenland

Finland joined NATO on April 4, 2023, turning its 833-mile border with Russia into a NATO frontier; more than 300 miles of it lies north of the Arctic Circle. Sweden followed on March 7, 2024. Russia’s defense minister reportedly said in December 2022 that Russia would reorganize forces near the Nordic countries in response, CRS reported.

Canada says it has reached NATO’s 2% defense spending target for the first time since the fall of the Berlin Wall. On July 6, Prime Minister Mark Carney named Germany’s TKMS as preferred supplier for up to 12 submarines, built on the 212CD design that he said is capable of Arctic patrol, according to his office. Ottawa said only one of its four current submarines is seaworthy. Contracts are due by the end of 2027 and the first four boats in 2034, with South Korea’s Hanwha Ocean as the fallback. Our earlier report covers Canada’s Arctic defence, ICE Pact talks and NORAD drills.

In Greenland, the U.S. military presence rests on a 1951 U.S.-Denmark agreement, updated in 2004, and is centered on Pituffik Space Base, formerly Thule Air Base, CRS says. In June 2025, the Pentagon was reported to plan moving Greenland from U.S. European Command to U.S. Northern Command. Europe is also moving: see our report on the EU Arctic strategy and its icebreaker plans.

What to watch

Watch three things: whether the Arctic-Pacific Partnership memorandum is signed in Atlanta tonight and what it commits the three governments to; Rosatom’s official 2026 Northern Sea Route totals after the season closes; and whether the first U.S. Arctic Security Cutter keeps its 2028 date. This report will be updated if the Atlanta signing produces new details.

Sources

• NSIDC: Arctic sea ice minimum ties for tenth lowest (Sept. 23, 2026)
• NSIDC Sea Ice Index v4: September monthly extent data
• Stroeve et al., “Changes in Arctic melt season and implications for sea ice loss,” Geophysical Research Letters (2014)
• CHNL: Main Results of NSR Transit Navigation in 2025
• CRS RL34391: Coast Guard Polar Security Cutter and Arctic Security Cutter programs (Jan. 21, 2026)
• CRS R41153: Changes in the Arctic, Background and Issues for Congress (July 14, 2025)
• U.S. Department of Defense: 2024 Arctic Strategy
• U.S. Coast Guard: Joint Chinese-Russian patrol in Bering Sea (Oct. 1, 2024)
• Prime Minister of Canada: Canadian Patrol Submarine Project (July 6, 2026)
• Yonhap: U.S., South Korea, Japan diplomats to sign Arctic-Pacific Partnership (Oct. 30, 2026)

Additional sources

• NSIDC: “Stranger Things” in the 2026 Arctic (Northwest Passage ice, September average)
• Remote Sensing (2018): Arctic melt and freeze season indicators (ice-free period trend)
• Environmental Research Letters (2017): NSR transit navigation from satellite data and CMIP5 (season projections)
• Marine Policy: NSR ship transits 2011–2018 (early transit counts)
• CHNL: NSR shipping activities in 2022 (2021–2022 counts) and NSR transits in 2023
• CHNL: Main results of NSR transit navigation in 2024 (Russia-China corridor)
• U.S. Coast Guard: Chinese research vessel activity in U.S. Arctic (Aug. 8, 2025)