A 3-million-year ice age is coming to an end

A dramatic animation shows how much of the Arctic sea ice has melted away in the last 35 years. The ice loss poses a terminal threat to polar bears

The Arctic sea ice, which polar bears depend on for survival, is shrinking.

A new study finds that ice is melting even earlier in spring than thought, and growing back later in autumn.

If this trend continues, polar bears will face longer periods without ice.

Watch how much their world has changed in 35 years in the video above. 

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