If you recently had a close encounter with the howling demon known as Superstorm Sandy, you might have a renewed belief in global warming. If not, consider yourself lucky, then see Jeff Orlowski's beautiful yet sobering documentary about the world's rapidly melting ice caps. His guide is James Balog, a renowned nature photographer who has become obsessed with documenting the staggering speed with which the icebergs of Greenland, Iceland, and Alaska are crumbling into the sea. Orlowski films as Balog and a small team of young scientists go on a mad mission to embed dozens of time-lapse cameras into the rock walls above various ice fields. Those cameras take one image every hour, and when Balog and his team, known as the "Extreme Ice Survey," assemble the footage, they discover that glacier fields the size of Lower Manhattan are receding at an astonishing rate. Still and live-action footage captures the ice sliding into the sea with exquisite grace, which makes it all the more wrenching. Are such images enough to convince the naysayers that something unnatural is occurring? Doubtful. After all, when the weatherman says a hurricane is coming, aren't there always those who refuse to leave their cozy dens?