"We have never seen such temperatures in November, so we do not know what this condition is doing on the cliff in the summer – and technically not summer."
One positive thing is that the temperature anomalies on the surface of the sea were not as big as during the same period before mass coral bleaching in the years 2015-16. This season included one of El Nino's most powerful events.
By contrast, although the conditions of the Pacific were prepared for El Nino – an event that usually leads to fewer cyclones outside of Australia and stylists, a warmer summer season – such an event still did not have to occur.
Also, a potential reduction in the risk of further mass bleaching was that the 2015-16 and 2016-17 seizures killed more sensitive corals and left harder survivors, Dr. Wachenfeld.
In the past, the corals would probably have been bleeding if they would last for four weeks of warming and began to die at eight. This meter – based on one-week equivalents with one degree of above-average conditions – is a sign of heat stress on beads, which encourages them to eject the lashes that give them the most energy and color.
"In fact, we do not expect these thresholds that we have applied in the past necessarily apply everywhere as strictly as they do," Dr. Wachenfeld told reporters. "Predicting the future is therefore much more difficult than a few years ago."
The conditions were undoubtedly unprecedented on the ground, where places like Cairns – a popular destination for visitors to the cliff – smashed the previous November heat records up to five degrees.
The short-term view, according to the meteorological office, is for those unusually warm conditions to prolong as long as another week.
Link to climate change
While scientists can analyze fingerprints at the current wavelength, Dr. Wachenfeld said that the Great Barrier Reef has warmed by 0.9 degrees over the past 200 years.
"If we continue the global trajectory we live in with regard to greenhouse gas emissions, all coral reefs in the world will have tremendous difficulties and we are likely to lose them by the end of the century," he said.
Dr. Wachenfeld has refused to comment on the development of the gigantic coal basin in central Queensland, including the Thursday announcement that Adani Carmichael will soon begin to build.
"It's not a place [the authority] to express our views on such concrete decisions, but on the national and global levels we need to adopt renewable energy, we need to get rid of fossil fuels, we need to find ways to reduce emissions. "
Peter Hannam is an environmental editor at the Sydney Morning Herald. It deals with broad environmental issues, from climate change to renewable energy for Fairfax Media.