In the last five years, the Great Barrier Reef has experienced its third mass bleaching event. The reason for the bleaching has possibly been caused by warmer ocean temperatures. This reef is 1400 miles long and it is a UNESCO World Heritage Site. It is the longest and largest coral reef in the world. Due to the widespread bleaching, it is in danger of losing its status. Some areas which were previously unaffected have undergone moderate or severe bleaching. The good news is that scientists have also found healthy coral pockets. One thing to be noted is that bleached corals are not dead corals. There is a pretty good chance that most bleached corals will recover on mild or moderately bleached reefs and survive this event. In the same way, coral mortality would increase on severely bleached reefs. Some major tourism areas, specifically the northern and central Great Barrier Reef, have shown only moderate bleaching. These reefs are expected to regenerate and survive. The UN has warned that 90 percent of the world's corals will die if temperatures increase by 1.5 degrees Celsius.
