In the 16 years since “An Inconvenient Truth” became an unlikely box-office sleeper and Oscar winner, the climate change documentary has grown into its own distinct subgenre — one that has to devise increasingly eye-catching ways to net the attention of viewers who may have heard the message before, but have yet to really internalize it. The Al Gore-led PowerPoint presentation of Davis Guggenheim’s film looks positively quaint beside the grandiose, you-are-there spectacle of “Into the Ice,” which keeps the science simple and instead concentrates on ravishing imagery to remind us of a grim, inarguable and oft-repeated reality: The ice caps are melting, and we are barely doing a thing about it.

The first theatrical feature by nature-focused Danish docmaker Lars Henrik Ostenfeld, “Into the Ice” may not be especially novel in form or function, but its immersive journey into Greenland’s ice sheet is enough of a wow to make it stand out against other, similarly themed works. Following what promises to be a busy festival run — kicking off as the opening film of CPH:DOX, before going on to Visions du Réel — Ostenfeld’s National Geographic-style film should be easily accommodated by a mainstream documentary distributor or major streaming service, though home viewing may slightly shrink the impact of its most breathtaking ice-exploring footage.

Structurally, Ostenfeld ostensibly builds his film around the exploits of three climate change scientists: glaciologists Jason Box and Alun Hubbard, and paleoclimatology professor Dorthe Dahl-Jensen. Previously featured in “Chasing Ice,” the 2012 doc that covered similar snowy terrain, the American Box serves as the film’s clearest explicator, his specific research into the alarming effects of increased precipitation on the melting ice often laid out in straightforward hand-drawn diagrams — sometimes lending the film the candid air of a conversation with a genial expert.

Briton Hubbard, by contrast, is the film’s daredevil adventurer figure, carrying its most elaborate and hair-raising real-life setpieces in the second half — most notably when he climbs by rope nearly 600 feet into a glacier’s moulin, a vast vertical shaft formed over centuries from an initial crack. The more academically inclined Dahl-Jensen, however, draws the short straw when it comes to screen time. After reverently introducing her as a scientist “with a capital S,” Ostenfeld finds little way to animate her research — entailing fascinating, forensic examination of millennia-old ice to build a long-term timeline of climate change — for the camera, and she recedes in favor of her two male counterparts.

Granular and methodical in their tracking of snowfall and rainfall over time, Box’s studies involve less derring-do than Hubbard’s, though by not-so-happy accident, he winds up at the center of one of the film’s most perilous, heart-in-mouth sequences. While accompanied by Ostenfeld and research partner Masashi Niwano, he is caught in a sudden, vicious snowstorm, from which the men must shield themselves by swiftly cutting and stacking giant bricks of ice. Their ordeal is the filmmaker’s good fortune. Acting as his own cinematographer, Ostenfeld captures this startling attack of the elements with remarkable poise and focus — a reminder of nature’s power even in the face of human destruction.

Still, the whole film builds to Hubbard’s record-breaking descent into the ice itself, as he aims to survey the state of the surface at the crevasse’s base. We’re teased with a fakeout. On the first trip down, conditions are deemed too dangerous for Ostenfeld and his camera to accompany them, and the scientists’ own footage is on the murky side. Second time, however, proves the charm, as the audience is fully party to their plunge into another world.

Walled by soaring expanses of white and iridescent blue, pointing up to the light like an alien cathedral, it’s a staggering, suitably humbling space, conveyed by a duly awed camera and crisp, echoing sound design. It’s a climax that counters the film’s doom-laden messaging with an unshakeable shot of thrill-seeking catharsis, though Hubbard’s anxiety over the instability of the glacier’s floor, and the ominous shifts and rumbles of the ice above, brings the point back home: Even this colossal natural structure is now fragile, at the mercy of changing conditions that, we are told, it would take another ice age to remedy. “Nature is trying to tell us something,” Ostenfeld concludes — and it’s worn out from the effort.