The first study to examine dates of spring sea ice retreat and fall ice advance across polar bear habitats around the Arctic has found that sea ice decline is hitting all 19 subpopulations of polar bears in the Arctic during the spring and fall, the times of year when they're most vulnerable.

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The first study to examine dates of spring sea ice retreat and fall ice advance across polar bear habitats around the Arctic has found that sea ice decline is hitting all 19 subpopulations of polar bears in the Arctic during the spring and fall, the times of year when they're most vulnerable.