‘Frozen Planet,” an enchanting seven-part series beginning Sunday night on Discovery, is the network’s latest high-def extravaganza. You know the drill: years in the making against extreme conditions, co-produced with those relentlessly determined British film crews who continue to press the limits of what a nature film can do to the mind. It joins “Planet Earth” and “Life” to reign as a triumvirate in Best Buy showrooms. Nothing looks better, sounds better.

The series travels to polar regions in the north and south. Its first episode establishes the vast, mysterious beauty of Earth’s coldest spots; each episode works its way through the subsequent four seasons and the hard-going life cycles of frigid inhabitants. There are penguins, whales, polar bears, seals, furry critters. There are Inuit natives hunting walrus and scavenging for mussels under tons of tidal ice. There’s that fabulous instant of spring awakening in northern Alberta, when a frozen waterfall cracks and dislodges a raging flow.

All of it narrated by Alec Baldwin’s chill gravel. Baldwin is cresting a wave of ubiquity that now includes credit-card commercials, podcasting, film roles, hosting gigs, airplane incidents and, of course, “30 Rock.” “Even polar bears enjoy a little bit of foreplay,” Baldwin says, as if about to enjoy some himself.

When “Frozen Planet’s” film crew captures rare footage of a team of killer whales swimming so precisely as to shake a delicious-looking seal off its ice floe, one can’t help imagining Baldwin’s narration as an elaborate Jack Don­aghy riff meant to explain the cruelty of fate to Tina Fey’s Liz Lemon. (“See that, Lemon? They wear him down until he can no longer wriggle away from their jaws. Don’t ever let them catch you napping on your floe.”)

But that’s just allowing one kind of television to intrude on another.

As it happened, Discovery accidentally sent me a screener for the “Winter” episode that included music but neglected to include the track with Baldwin’s voice. This is “Frozen Planet’s” darkest, most teeth-chattering part, and without narration, it was up to me to discern what I was seeing, which made it all the more mysterious and even more dreamlike. As winter grips Antarctica’s coast, “Frozen Planet’s” team journeyed under the ice to meticulously document the formation of “brinicles” — columns of frozen seawater — that snake down, tornado-like, to the ocean floor. In sped-up footage, the brinicles appear to flash-freeze all the starfish on the bottom.

Documentary specials of this caliber are the TV equivalent of quaaludes. “Modern Family’s” Phil Dunphy takes the best approach to such fare — propped on his couch, headphones on, eyes glazed over as his big-screen TV glows with undersea marvels. Phil catatonically melds with it, until his wife, Claire, thunks him on the head. (“PHIL!!”)

Documentaries like this are also nearly critic-proof, unless the critic wants to busy himself asking too many questions about how the darned thing was made, to the point of cross-examining the narrative: Is this female polar bear climbing a mountain to do the deed with her newfound mate indeed the same polar bear we saw a few minutes ago traversing an icy plain? Is this seal meeting his demise with another goon squad of killer whales the same fella we were watching elude them earlier? Do the clouds whip over antarctic peaks that fast or is that time-lapse?

Hush, now — shh. Talk too much and you’ll ruin it. “Frozen Planet” is best enjoyed as a whiteout storm across the mind. (Some of your curiosity about how it was made is addressed in a “making of” chapter April 8.)

With all the icing-over, oozing, spreading and melting, “Frozen Planet” offers an odd and perhaps deceptive reassurance. With so much talk of the climate catastrophe that looms in our future, it’s good to see the big Earth machine determinedly doing its thing. “Frozen Planet’s” objectivity and travelogue feel may test the patience of committed environmentalists, who must wait until the next-to-last episode (“On Thin Ice”) for the series to address scientific evidence of what’s happening to the ice caps.

A spooky and even mournful feeling runs deep beneath “Frozen Planet’s” smooth surface. Is this a celebration of the icy realm or a farewell retrospective?

Frozen Planet

(two hours) premieres Sunday at 8 p.m. on Discovery. Continues weekly through April 15.