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 are 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.)