'Chasing Coral'

U.S. Documentary; 93 minutes.

The beauty of "Chasing Coral" is matched only by its urgency, as director Jeff Orlowski encapsulates the issue of global climate change by showing where it's doing real, measurable damage in real time: The world's coral reefs.

Orlowski interviews an array of marine biologists who study coral reefs, which are to the ocean what trees are to rainforests: An anchor for an entire ecosystem. So when these scientists saw instances of "bleaching" — colorful coral suddenly turning clear white — they scrambled to find an explanation.

What they found is that the microscopic algae inside the coral, which form a symbiotic relationship with the coral by producing the food on which the coral grow, were dying. The reason the algae is dying is a 2-degree rise in ocean temperature, caused by the heat trapped by carbon dioxide emissions. (The oceans absorb 93 percent of the heat generated by the greenhouse effect.)

Getting that scientific information to the public has become the life's mission of Richard Vevers, a former ad executive who decided the ocean needed a better marketing campaign. Vevers enlisted Orlowski, whose Oscar-nominated "Chasing Ice" chronicled the slow retreat of the world's glaciers, using time-lapse photography to document the shrinking ice.

Orlowski assembles a team of technicians to modify time-lapse cameras for underwater use, and deploys them near Hawaii, Bermuda and the Bahamas. And when the high-tech approach fails, coral-obsessed cameraman Zack Rago and Orlowski (who learn scuba to make this film) film old-school, diving to the same location every day for a month.

The resulting footage, on which this powerful documentary climaxes, is heartbreaking. It also drives home the message Vevers and the scientists desperately want to convey: That the science is settled on global climate change, and that humans must cut carbon emissions now.

– Sean P. Means