Australia's Great Barrier Reef should be listed as a world heritage site that is "in danger," a U.N. panel recommended Tuesday, saying the world's biggest coral reef ecosystem was significantly impacted by climate change and the warming of oceans.
Frequent bleaching events are threatening the reef, including four over the last seven years and the first during a La Nina phenomenon — which typically brings cooler temperatures — this year.
Bleaching happens when the water warms too much, causing corals to expel the colorful algae living in their tissues and turn white.