Unprecedented coral bleaching in consecutive years has damaged two-thirds of Australia's Great Barrier Reef, aerial surveys have shown.
The bleaching - or loss of algae - affects a 1,500km (932 miles) area of the reef, according to scientists.
The latest damage is concentrated in the middle section, whereas last year's bleaching hit mainly the north. Experts fear the proximity of the two events will give damaged coral little chance to recover.
Prof Terry Hughes, from James Cook University, said governments must urgently address climate change.
Great Barrier Reef: Two-thirds damaged in 'unprecedented' bleaching
