In “An Inconvenient Sequel,” Al Gore continues to take on global warming

★★¼5

In a time when climate change seems an issue more vital than ever — especially as the Trump administration moves to dismantle programs meant to slow global warming and withdraws from global environmental partnerships — it is odd to find oneself in the position of saying this: The new documentary about Al Gore’s continued climate crusade lacks urgency.

It’s not the fault of the former vice president, who continues — with fervor — his campaign to school people about global warming, but a weakness of the film, “An Inconvenient Sequel: Truth to Power.” A follow-up to Davis Guggenheim’s Oscar-winning 2006 documentary, the sequel by Bonni Cohen and Jon Shenk covers much of the same ground of the first film, but with a tone that feels, at times, midway between a sense of resignation and despair. Those emotions might not be entirely foreign to Gore himself, who speaks, in the film, of his frustration and his struggle to remain hopeful in the face of political inertia (or outright backpedaling).

As in the first film, Cohen and Shenk follow Gore as he takes his climate-education road show around the world, interspersing clips of his public talks about climate science with more private moments in which he speaks of his emotions. More depressing even than the images of ecological disaster that the film traffics in — including scenes of floods in Miami and glacier loss in Greenland — is Gore’s dismal, but probably accurate, assessment of what needs to be done before we can save the planet: