30 March, 2016

Great Barrier Reef coral bleaching at 95 per cent in northern section -- attributed to global warming

What bulldust!  For a start, coral bleaching is NOT coral death.  It is a stress response that leads to the expulsion of symbiotic algae.  There are about half a dozen things that can cause it.  And the ONE thing that can be excluded as a cause is anthropogenic global warming.  Why?  Because there has been none of that for nearly 19 years.  Things that don't exist don't cause anything.

The ocean waters MAY have warmed but that will be due to natural factors such as El Nino.  The 2015 and early 2016 temperature upticks were DEMONSTRABLY due to El Nino and other natural factors, as CO2 levels were plateaued at the relevant time.

And it is not at all certain that a small temperature rise causes bleaching.  An ancient coral reef specimen now on display at the Natural History Museum in London is instructive.  It goes back to  160 million years ago.  The exhibit is proof that ancestors of modern corals somehow thrived during the Late Jurassic period when temperatures were warmer and atmospheric levels of carbon dioxide higher than they are today.

And if that's ancient history, how come corals survive in the Persian Gulf today at temperatures up to 8 degrees hotter that what we see in the tropical Pacific?

Bleaching may even be a positive thing. In recent years, scientists have discovered that some corals resist bleaching by hosting types of algae that can handle the heat, while others swap out the heat-stressed algae for tougher, heat-resistant strains.

And a recent study by the Australian Institute of Marine Science showed that warming in Australian waters actually INCREASED coral growth over the 20th century: "Study finds coral reef growth thrives in warmer waters"

I could go on but I think I have said enough

All the points I have made above could have been made by any competent marine biologist -- and I can provide references for them all. But I am not a marine biologist. I am a psychologist. What a harrowed world we live in where a psychologist has to give the basic information that marine biologists dare not give.


An aerial survey of the northern Great Barrier Reef has shown that 95 per cent of the reefs are now severely bleached — far worse than previously thought.

Professor Terry Hughes, a coral reef expert based at James Cook University in Townsville who led the survey team, said the situation is now critical.

"This will change the Great Barrier Reef forever," Professor Hughes told 7.30.

"We're seeing huge levels of bleaching in the northern thousand-kilometre stretch of the Great Barrier Reef."

Of the 520 reefs he surveyed, only four showed no evidence of bleaching.  From Cairns to the Torres Strait, the once colourful ribbons of reef are a ghostly white.

"It's too early to tell precisely how many of the bleached coral will die, but judging from the extreme level even the most robust corals are snow white, I'd expect to see about half of those corals die in the coming month or so," Professor Hughes said.

This is the third global coral bleaching since 1998, and scientists have found no evidence of these disasters before the late 20th century.

"We have coral cores that provide 400 years of annual growth," explains Dr Neal Cantin from the Australian Institute of Marine Science.

"We don't see the signatures of bleaching in reduced growth following a bleaching event until the recent 1998/2000 events."

Environment Minister Greg Hunt flew over the reef just eight days ago, before Professor Hughes' aerial survey, and announced some additional resources for monitoring the reef.

"There's good and bad news — the bottom three quarters of the reef is in strong condition," he said at the time.

"[But] as we head north of Lizard Island it becomes increasingly prone to bleaching."

The northern part of the Great Barrier Reef is the most pristine part of the marine park — and that is one possible glimmer of hope.

"On the bright side, it's more likely that these pristine reefs in the northern section will be better able to bounce back afterwards," Professor Hughes said.

"Nonetheless we're looking at 10-year recovery period, so this is a very severe blow."
'We're seeing climate change play out across our reefs'

Professor Justin Marshall, a reef scientist from the University of Queensland, said the reason for these bleaching events was clear.

"What we're seeing now is unequivocally to do with climate change," he told 7.30.

"The world has agreed, this is climate change, we're seeing climate change play out across our reefs."

Professor Hughes said he is frustrated about the whole climate change debate.

"The government has not been listening to us for the past 20 years," he said.

"It has been inevitable that this bleaching event would happen, and now it has.

"We need to join the global community in reducing greenhouse gas emissions.

SOURCE





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