Great Barrier Reef could face another big coral bleaching event this year

New report to UN world heritage committee criticises Australia's lack of planning in dealing with effects of climate change

The Great Barrier Reef faces an "elevated and imminent risk" of more widespread coral bleaching this year, the reef authority has warned the Queensland government.

An alert from the Great Barrier Reef Marine Park Authority says more of the reef is showing built-up heat stress than this time last year, just before its worst-ever bleaching event killed off a quarter of all coral.