Aerial surveys of Australia’s Great Barrier Reef conducted in late 2016 and early 2017 show the Unesco world heritage site has suffered severe coral bleaching for the second year in a row. Bleaching comes when heat stress forces corals to expel tiny photosynthetic algae, which leaves them white. Scientists say fast-growing coral takes 10 to 15 years to fully recover from bleaching. A study found that 91% of coral on the Great Barrier Reef had suffered from bleaching over the past two decades.
New bleaching at the Great Barrier Reef
