Climate change denial must be maddening to Lonnie Thompson, a respected scientist who has scaled glaciers collecting evidence of global warming. But Dr. Thompson keeps a cool head in “Canary,” a documentary that patiently traces his groundbreaking efforts extracting ice cores from tropical mountaintops.
The film, directed by Danny O’Malley and Alex Rivest, is a portrait of perseverance. Inspired by a student research opportunity to look at polar ice cores, Dr. Thompson wondered whether other parts of the world could also yield useful ice samples. To paraphrase George Bernard Shaw, some colleagues looked at tropical glaciers and asked “why,” while Dr. Thompson saw their potential for climatology and asked “why not.”
His expeditions to the Quelccaya ice cap in Peru in the 1970s and ’80s required transporting heavy equipment and using solar power. Dr. Thompson, 75, with grandfatherly humility, recounts his career’s progress in the film’s frankly long-winded account, aided by stills, some archival footage, and scientists and family members, including his wife and research partner, Ellen Mosley-Thompson, who is a glaciologist and climatologist.
Dr. Thompson’s ice cores show how recent temperature changes have been highly unusual compared to past centuries. The issue of human-caused global warming gets traction in the 1990s with political and media attention, but damning clips show politicians in the 2000s affirming the urgency of the issue one moment, then backtracking into equivocation. First global warming needs to be addressed, then suddenly nobody is sure if the science is definitive.
The political inertia receives a quietly provocative parallel in Dr. Thompson’s life: He delayed treating a serious heart scare because of stubborn disbelief. The health of the planet, the film seems to say, also depends on acting before it’s too late.
Not rated. Running time: 1 hour 44 minutes. In theaters.