Chasing Coral

An advertising man, a diver and a group of scientists set out to record the moment coral reefs bleach. The idea looks simple: put time-lapse cameras underwater, leave them for months, show the change. The execution keeps collapsing, with cameras fogging, focus drifting and data lost, until the team has to make the record by hand, diving every day. Jeff Orlowski's film folds that technical failure into the story. At its centre is the mass bleaching that hit the Great Barrier Reef in 2016, where a rise of a few degrees makes the coral expel the algae it lives with and then starve. It took the audience award at Sundance and went out on Netflix. Who it is for: viewers who like climate documentary and underwater photography. Who it is not for: anyone who does not want bad news, since the film offers no consolation.