The last bastion of Arctic ice, the Nares Strait that separates Greenland from Canada, is also at risk.
Data from the Copernicus Sentinel 1 satellite shows that ice stability in the area has decreased over the past 20 years.
Published in the journal Nature Communications, the discovery is due to researchers coordinated by physicist Kent Moore of the Canadian University of Toronto.
"This very ancient ice worries us," notes Moore.
The Nares Strait is the oldest and thickest ice sheet in the Arctic region and has managed to survive even the hottest summers on record to date, but research suggests it may be more vulnerable than imagined.
Using data from the Copernicus Sentinel 1 satellite, managed by the European Space Agency (ESA) and the European Commission, the researchers examined the stability of structures called ice arches that form seasonally at the northern and southern ends of the Nares Strait.
These structures form a natural barrier that prevents sea ice from moving out of the Arctic Ocean and drifting south and typically break apart in late spring, only to reform in winter.
According to observations, over the past 20 years the ice arches have become thinner and every year they break a week earlier than the previous year.
In practice, they are becoming less and less a barrier and this could destabilize the northernmost area called the Last Ice Area, which is an important refuge for ice-dependent species, from polar bears to icy algae that provide oxygen and nutrients to the environment.
