Not because of any human input. ... If the reef dies off...
Climate change and global warming are both total nonsense and drivel concepts.
The Sahara Desert started growing 7 million years ago due to changes in the ocean currents and movement of continents into different climate zones. Not because of any human input. The Great barrier reef is always in state of flux and movement. If the reef dies off in the northern sector it grows equally in the southern region. Bleaching is mostly a result of tourists who take away important shell fish that keep coral predators in check. Once you remove all the shell fish that eat the Crown of Thorns Star Fish you get reefs being eaten away until they go all white. This is nothing to do with the climate.