Devastating global coral bleaching event could hit Great Barrier Reef next

Australia's world heritage-listed reef is threatened by warmer waters that have killed off coral in Fiji but the full impact depends on the weather

The third global coral bleaching event to be recorded is snaking its way around a warming globe, devastating reefs and now threatening the world-heritage listed Great Barrier Reef.

This week it was announced the bleaching event, which began in 2014, is already the longest in history and could extend well into 2017. "We may be looking at a two- to two-and-a-half-year-long event. Some areas have already seen bleaching two years in a row," says Mark Eakin, coordinator of the Coral Reef Watch program at the US National Oceanic and Atmospheric Administration.