Storms, starfish and climate change have really taken a tole on the Great Barrier Reef, a new study in Proceedings of the National Academy of Science shows. In the past 27 years, half of the coral cover over the reef has been lost. If the current rate of coral loss continues by 2022 that which remains could be reduced by half again.
Storm damage from intense tropical cyclones is responsible for just under half the observed coral decline, crown of thorns starfish, which eat coral, have destroyed slightly over 40%, with coral bleaching accounting for 10%.
Peter Doherty form the Australian Institute of Marine Science says, "Interestingly, the pattern of decline varies among regions. In the northern Great Barrier Reef coral cover has remained relatively stable, whereas in the southern regions we see the most dramatic loss of coral, particularly over the last decade when storms have devastated many reefs."
Though coral reefs can general recover from this sort of damage, such recovery can take a decade or two, and there hasn't been enough time between damaging incidents for the Great Barrier Reef to recover.