In recent decades, humans have lost 25 to 40 percent of the world's corals due to seawater temperature rise and ocean acidification. Dr David Vaughan has been studying corals his whole life, but until eight years ago, could only watch the crisis unfold. After an accident one day in the lab, Vaughan discovered a secret of coral reproduction, and is now working to replant dwindling coral reefs at an astonishing rate. The Atlantic visited Dr Vaughan in the Florida Keys to uncover how the process works and understand how much hope there is to revitalize our reefs.