Editor’s Note: Call to Earth is a CNN editorial series committed to reporting on the environmental challenges facing our planet, together with the solutions. Rolex’s Perpetual Planet Initiative has partnered with CNN to drive awareness and education around key sustainability issues and to inspire positive action. CNN  —  Crashing waves, glistening sea spray, a calm expanse of deep blue. These are the images that open “Ocean with David Attenborough,” the veteran broadcaster’s latest film. After