“My dad spends every day looking at climate change,” Regina Thompson says of her father, the paleoclimatologist Lonnie Thompson, in the new documentary “Canary.” Her dad drills ice-core samples on the world’s glaciers, archiving a record of climate history going back thousands of years. And while doing that, he couldn’t help but notice all the glaciers were in retreat, melting away.

Her father wonders, she says, “Why the disbelief? What do you (climate-change deniers) not understand?”

Lonnie Thompson, who appeared in the Oscar-winning and Nobel Prize-linked documentary “An Inconvenient Truth,” figured this out in the late 1970s and began publishing and sounding the alarm not long after. Now in his ’70s, he speaks in “Canary” of his “failure” to help turn the world’s thinking around on burning carbon for energy, despite the seeming consensus on this issue in the early 2000s.

“If I’d been successful,” he says, “we’d have changed the trends.”

As filmmakers Danny O’Malley and Alex Rivest make clear in “Canary,” it’s not Thompson’s efforts that fell short. It was an engineered campaign of climate denial by Big Coal, Big Oil and those shortsighted and cynical enough to underwrite politicizing “the biggest challenge we face as a civilization, human-caused climate-change.”

But their film is about a scientist who was almost a lone voice in the wilderness when he took notice of something long predicted-and-speculated upon, that human activity was warming the climate. Peers, journalists and authors refer to him as a “real-life Indiana Jones,” a pioneer in getting ancient climate data for researching climate trends through history, and their impact, by climbing the most remote glaciers on Earth — Peru to Papau, Indonesia — to drill core samples.

Lonnie Thompson was a farm lad growing up in Gassaway, West Virginia, when he discovered a love of science and a knack for predicting the weather. He went to college, and studied geology as an undergrad, and started graduate school at Ohio State as a “coal/geology” student, befitting a young man from “Coal is King” country.

When he was turned down for a chance to join a team led by an Arctic and Antarctic pioneer in this field of using ice cores to see what the weather was like throughout history, he found his place on the “in-between” ice caps in the Peruvian Andes, on a mountain in the middle of a rainforest island north of Australia, “impossible” to reach places where natives were often in conflict with outsiders coming to do research.

Thompson and his glaciologist/climatologist wife Ellen Mosley-Thompson were doing the early research that became the basis for international consensus on sounding the alarm over climate change.

“Canary” — it takes its title from the old “Canary in the coal mine” signal that the air had turned bad — is mostly a straightforward biography of a modest, sober-minded man of science struggling to get his life’s work (core sampling everywhere that’s possible) completed and getting that work to mean something in the face of advancing years, failing health and “the biggest challenge we face as a civilization — human-caused climate change.”

“Canary” is a fairly dry film, narrow in focus, but it can be inspiring. And in that one montage, where conservative American politicians from Gingrich and Palin to Romneybabdt others abruptly flip-flop their stances on the “inconvenient truth” staring everybody in the face by the mid-2000s, it’s just dismaying.

A lot of America adopted its anti-science, anti-climate change politics from that era and has dogmatically failed to be shaken by any and all evidence that they were being lied to by energy lobbyists and their political hirelings.

And here we are, looking at a film about a scientist who devoted his life to gathering data and facts and making the case that what he was learning was a call for urgent action, action that it seems impossible to take thanks to people who refuse to see and grasp the obvious.

Rating: unrated

Cast: Lonnie Thompson, Ellen Mosley-Thompson, J. Madeleine Nash, Frances Thompson, many others

Credits: Directed by Danny O’Malley and Alex Rivest. An Oscilloscope Labs release.

Running time: 1h44

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