Canada’s defence community is continuing to pay attention to the impacts of lessening Arctic sea ice, as NASA recently reported the ice reached its lowest annual minimum this year on Sept. 10.
The total sea ice coverage for 2025’s minimum tied with 2008 for the tenth lowest on record, NASA stated. The ice amount was 4.6 million square kilometres – roughly half the equivalent square area of the whole of Canada. And that has defence implications.
“With retreating sea ice and new technologies improving navigation and accessibility, foreign activity in the Arctic will continue to increase, bringing with it related safety, security and environmental challenges. With other Arctic states, Canada must be prepared to respond,” states Canada’s Arctic Foreign Policy.
The policy specifically mentions Russia as a principal threat in this regard, citing the country’s “illegal war in Ukraine” as one of the drivers. But climate change and “increased competition and geopolitical tension” generally in the Arctic also are factors.
While the policy emphasizes that the Arctic “is a region of tremendous opportunity thanks to its plentiful resources and resilient people,” lessening sea ice has raised concerns among Indigenous peoples, and others living in the north, about matters including infrastructure and food security. If ice does not persist year-round as ecosystems have had in the past, residents have warned, more issues will arise including wildfires and “subsidence” (ground sinking), the policy states.
Canada has been increasing its Arctic surveillance in recent years, and pledged in 2024 to purchase up to 12 “conventionally powered, under-ice-capable submarines” as well as to procure eight new Canadian-made icebreakers. Canada is one of many countries that uses satellite data in preparing for these missions, as well as for helping northern communities more generally with mitigating the impacts of lessening sea ice.
As NASA explains, some melting is expected naturally: ice builds up as the seawater freezes, and then will melt in the summer months when temperatures rise. But what the agency and the National Oceanic and Atmospheric Administration (NOAA) have noticed, since tracking of sea ice began in 1978, is that “sea ice extent has generally been declining as global temperatures have risen” through human-driven climate change.
“We’ve hit 47 years of continuous monitoring of the global sea ice extent from satellites,” said Angela Bliss, assistant chief of NASA’s cryospheric sciences laboratory, in the agency statement about this year’s ice pack. “This data record is one of the longest, most consistent satellite data records in existence, where every single day we have a look at the sea ice in the Arctic and the Antarctic.”
Satellites participating in this effort have included NASA Nimbus-7 satellite (1978–1987); sensor collections on Defense Meteorological Satellite Program satellites that began in 1987; microwave scanning aboard NASA’s Aqua (2002-2011) that was extended aboard a JAXA satellite; and ICESat-2 starting in 2018, NASA stated.
The lowest recorded sea ice extent was in 2012; while this year at first appeared to be going on that track, melting slowed down around early August, NASA noted. The overall trend nevertheless shows that the Arctic Ocean’s ice coverage continues to fall below 2007 levels, which is a trend seen for the past 19 years.