The money shots come late in “Chasing Ice,” a documentary about the pioneering glacier photography of James Balog. For more than an hour, we’ve followed him around Iceland, Greenland, and Alaska, as he and his assistants set up cameras facing the great ice sheets, programming them to snap photos at regular intervals. Finally we get the big reveal: The images are arranged as time-lapse sequences in which glaciers melt away like so much butter over the course of a year. As much as one may intellectually believe in climate change, to see it actually happening has the power to stun a viewer into wordlessness. Balog’s work is flip-book apocalypse, and it is undeniable.

The rest of Jeff Orlowski’s film works hard to build up its subject as an obsessive craftsman saint, and that feels vaguely beside the point. Ultimately, it’s the pictures that matter and not the man who takes them. But Orlowski does share Balog’s smoldering rage at a society that refuses to face the consequences of its actions, and that rage forms the necessary spine of “Chasing Ice.” This is an agit-doc with no apologies and a lot of sorrow.