Coral bleaching 'has changed the Great Barrier Reef forever' – video

Terry Hughes from James Cook University in Queensland leads a taskforce measuring the condition of the Great Barrier Reef amid a global coral bleaching event that is 'off the scale'. 'The kind of bleaching we're seeing now is an entirely modern phenomenon,' he says. 'We're now in a very precarious position, where every El Nino that comes along, every five or six years, can potentially bleach the entire Great Barrier Reef'

" Great Barrier Reef: a catastrophe laid bare - special report