A delegation from the United Nations recommended Tuesday that the Great Barrier Reef be listed as a World Heritage site in danger, urging the world to act quickly to rein in climate change or risk losing the planets largest coral ecosystem.

The U.N. mission, a joint effort by UNESCO and the International Union for the Conservation of Nature, said in a new report that climate change continued to significantly affect the outstanding universal value of the reef. Without ambitious, rapid and sustained action, the sites celebrated biodiversity and beauty remain in grave danger.

The GBR has suffered a series of widespread coral bleaching events, occurring with increasing frequency, including four events over the last seven years, the authors wrote. The mission team concludes that the property is faced with major threats that could have deleterious effects on its inherent characteristics, and therefore meets the criteria for inscription on the List of World Heritage in Danger.

The report recognizes that climate change is a world issue that cant be fixed by Australia alone. But the mission urged the country to adopt emissions targets that would dramatically limit greenhouse gases and protect water quality around the reefs, among 10 priority goals listed in the report.

Officials from UNESCO, the U.N. agency that monitors world sites of outstanding universal value , visited the Great Barrier Reef in March, just as it was undergoing another devastating mass coral bleaching event. Coral bleaching most often occurs when hotter-than-normal seawater in effect cooks delicate coral polyps.