The conclusions are in from a series of scientific surveys of the Great Barrier Reef bleaching event - an environmental assault on the largest coral ecosystem on Earth - and scientists aren't holding back about how devastating they find them.
Australia's National Coral Bleaching Task Force has surveyed 911 coral reefs by air, and found at least some bleaching of the vast majority of them. The bleaching was the worst in the reef's remote northern sector - where virtually no reefs escaped it.
"Between 60 and 100 per cent of corals are severely bleached on 316 reefs, nearly all in the northern half of the Reef," Professor Terry Hughes, head of the ARC Centre of Excellence for Coral Reef Studies at James Cook University, said. He led the research.
Severe bleaching means that corals could die, depending on how long they are subject to these conditions. The scientists also reported that based on diving surveys of the northern reef, they already are seeing nearly 50 per cent coral death.