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Are they serious? Shade Cloth over the Great Barrier Reef to save it from climate change?

These people are not good with numbers.

In a paper published in Nature Climate Change today, Ove Hoegh-Guldberg, director of the Global Change Institute at the University of Queensland, together with Greg Rau of the Institute of Marine Sciences at the University of California, and Elizabeth McLeod of The Nature Conservancy, say new tactics are needed to save oceans from CO2 emissions.

“It’s unwise to assume we will be able to stabilise atmospheric CO2 at levels necessary to prevent ongoing damage to marine ecosystems,” Professor Hoegh-Guldberg said.

“In lieu of dealing with the core problem – increasing emissions of greenhouse gases – these techniques and approaches could ultimately represent the last resort.”

In addition to using shade cloth over coral reefs, the paper suggests novel marine conservation options, including applying low-voltage electrical current to stimulate coral growth and mitigate mass bleaching; adding base minerals such as carbonates and silicates to the ocean to neutralize acidity; and converting CO2 from land-based waste into dissolved bicarbonates that could be added to the ocean to provide carbon sequestration.

Alistair Hobday Research Scientist – Marine and Atmospheric Research at CSIRO said novel solutions are required. “We need to be mature enough to listen to all sorts of arguments.”

To which Jo Nova,  unfunded non government critic said: We need scientists who are mature enough to spot a plan that is bonkers.

The Great Barrier Reef has an  area of 348,000 square kilometers. It’s bigger than the UK, Holland and Switzerland combined. So perhaps we could just cover 1%, that’s only three and a half thousand square kilometers and then ask the water to stay in one spot?

The idea apparently is not to drive thousands of pylons into the reef (phew), just to cover “hundreds of square meters” with floating shade material.  One wonders how predatory sea-birds will feel about this, not to mention photosynthetic marine life. Air breathing mammals might not “feel right at home” under the shades. (But its not like anyone cares about whales and dolphins right?) Tidal and wave action, with floating material near lots of spiky coral and rocks suggests maintenance could be “expensive”.

The cost? Who knows?

I have no idea what floating shades will cost. It’s probably nothing like land shades, and doesn’t need the poles but will need anchor cables (or there will be a new hazard in shipping lanes). Failing any details, I’ve costed the land sails option here, just for a ball park, give or take $100m (or a billion here and there).

If shade sails on land cost $2,800 to cover 6m by 5m (30 m2), assuming bulk discounts can keep the price the same (even though the installation may be 100km offshore, in salt water, and pounded constantly by waves) that’s only 33,333 shade sails to the square kilometer, at a cost of $93m. All up, covering 1% of the reef (if that were the aim, though it appears not to be that ambitious) is about $300 billion. That’s more than ten times Australia’s annual defense budget. What could possibly go wrong?

The commenters at The Conversation are a case study in why free speech is its own reward. People are volunteering to correct the nonsense put out by paid scientists and paid journalists. It takes months of work to flesh out a really gonzo idea, and yet it takes people five minutes for free to explain the flaws. Why do we spend tax dollars to employ people to be silly? Why didn’t the “editor” run the idea past a skeptic? Why does Nature Climate Change publish this type of material? (And for that matter, when will The Conversation discover that they can add links in their articles?)

We paid $6m to set up The Conversation. Why?

What we do need is something novel — we need a practical review of the empirical evidence to figure out whether we need to bother doing anything to reduce CO2 levels.



Wade Macdonald, Technician

No doubt the GBR faces some threats but the idea of putting up shade cloth in amongst cyclone ravaged reefs sounds like a great way to create plenty of ‘shade cloth drift nets’ and kill more biodiversity than it would save. What about all the international ships that pass through the area and other vessels?

Who are these people and where did they get the qualifications from?

Stop listening to the fear campaigners and learn the truth….

Quote… “At the scale of the whole GBR, there was no net decline in hard coral cover between 1995 and 2009.”


Trevor Ellice, Geologist



– what are you guys smoking?

or this just an old fashioned doomsday cult?


Rau, G., McLeod, E.L. &  Hoegh-Guldberg, O. (2012) The need for new ocean conservation strategies in a high-carbon dioxide world   Nature Climate Change doi:10.1038/nclimate1555

Anthony Watts thinks this could be the wackiest climate change technology proposal ever.

h/t George J. With thanks to the BOM Audit team for feedback.


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