Peter Ridd, physicist, marine scientist: In 2016, there was a major bleaching event in the northern section of the Great Barrier Reef. The worst affected area for that event, around Lizard Island where coral cover halved, has now totally recovered. It only took 5 years. The bleaching certainly caused the worst mortality in this area since records began in 1985. In this period, it had not been smashed by cyclones like other areas further south. In future posts I’ll show some other regions with huge natural changes in coral cover.