This heartbreaking documentary puts a face on the sad statistics of global warming--and though it's not a human face, it's the perhaps even more effective face of an adorable polar bear cub, Nanu, along with her mother, her brother, and her natural enemy, the equally heart-melting Seela the walrus. With breathtaking footage of life on the arctic tundra, the directors spin a highly emotional tale of the melting ice caps and the effect of their disappearance on every species in the ecosystem.

Since the film is essentially aimed at children, the cuteness factor is off the charts, aided by the slightly grating use of sound effects, a slangy voiceover by Queen Latifah, and a kid-friendly pop/folk soundtrack. And, as in a National Geographic special, viewers learn some interesting and neutral facts about polar bears, walruses, narwhals, foxes, and other northern creatures. The narrative, however, returns repeatedly to the grim conditions that are killing off our planet's wildlife, one family at a time. The directors take pains to create a hopeful ending, with a sweet pair of life-goes-on epilogues and a closing credit sequence featuring conservation tips, but the message of the film is sobering and hits its mark with kids and adults alike.