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 (900 miles) stretch 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.
James Cook University said governments must urgently address climate change to prevent further bleaching.
Coral bleaching is caused by rising water temperatures resulting from two natural warm currents.
It is exacerbated by man-made climate change, as the oceans are absorbing about 93% of the increase in the Earth’s heat.
Bleaching happens when corals under stress drive out the algae known as zooxanthellae that give them color.
If normal conditions return, the corals can recover, but it can take decades, and if the stress continues the corals can die.