Polar bears living in the Arctic lost about 40 per cent of their population in the last decade, according to a new study by US and Canadian scientists.

A polar bear cub. Photo: Getty

The loss was particularly bad in the years 2004 to 2007, in which polar bears in the southern Beaufort Sea struggled to find seals for food due to thinning ice.

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“Of the 80 cubs observed in Alaska from 2004 to 2007, only two are known to have survived,” said Jeff Bromaghin, US Geological Survey research statistician and lead author of the study in the journal Ecological Applications.

Thankfully, survival improved after 2007 and the population stabilised at 900 bears by the year 2010.

However, when looking just at juveniles, the research showed their numbers declined throughout the 10-year-period, suggesting that “conditions remained unfavourable for young bears newly separated from their mothers”.

Polar bears are considered a globally threatened species, due to concerns about how ice loss affects their ability to survive.

Co-authors on the study came from Environment Canada, University of Alberta, the US Fish and Wildlife Service, Polar Bears International and Western Ecosystems Technology.

— with AAP