Local Extinction of Polar Bears in Canada’s Hudson Bay if Global Warming Exceeds 2°C

Communications Earth & Environment, 13 June 2024

The Hudson Bay polar bear population, comprising three of the world’s 19 remaining groups (about 4000 individuals), will go locally extinct in the next few decades if today’s emissions continue, a study this week found. This is due to projected loss not only of sea ice extent, but its thickness, which must be sufficient to hold the weight of the bears as they hunt. The study found that once temperatures pass 2°C, the three Hudson population groups would have insufficient strong, thick ice for enough of the year to survive. The Bay loses all ice in summer, forcing bears to come ashore until ice re-forms in fall, allowing them to resume hunting for seals. They do not eat during this ice-free period; and decreases in ice coverage already are likely responsible for a halving of the Western Hudson Bay bear population since 1987. Presaging this possible future without urgent fossil fuel reductions, unusually high temperatures and strong winds caused an early Hudson Bay ice break-up this year, with the region hitting record-low ice extent for May since satellite records began in 1979.

https://www.nature.com/articles/s43247-024-01430-7