This documentary-drama hybrid explores the dangerous human impact of social networking, with tech experts sounding the alarm on their own creations.

Coral reefs are the nursery for all life in the oceans, a remarkable ecosystem that sustains us. Yet with carbon emissions warming the seas, a phenomenon called “coral bleaching”—a sign of mass coral death—has been accelerating around the world, and the public has no idea of the scale or implication of the catastrophe silently raging underwater.

When National Geographic photographer James Balog asked, “How can one take a picture of climate change?” his attention was immediately drawn to ice. Soon he was asked to do a cover story on glaciers that became the most popular and well-read piece in the magazine during the last five years. But for Balog, that story marked the beginning of a much larger and longer-term project that would reach epic proportions.