The new normal (part 22): The Great Barrier Reef is dying

Source: The Age

A little over two years ago I took my first trip to north Queensland with the express purpose of seeing the Great Barrier Reef (GBR) and the magnificent rain forests of the region. I was motivated by the thought it may be one of those “last chances to see” the GBR before its inevitable decline.

While there I could no help but feel a muted, but still profound, sense of melancholy.

I could not help but recall my child hood experience of watching David Attenborough’s Life on Earth. What I saw was beautiful, complex and fascinating and yet fragile and at risk.

For some time scientists have understood the Great Barrier Reef is at risk – today a report in The Age today confirms that over the past 30 years half of the GBR’s coral has disappeared due to parasites, cyclone damage and coral bleaching:

Half the Great Barrier Reef’s coral has disappeared in the past 27 years and less than a quarter could be left within a decade unless action is taken, a landmark study has found. 

A long-term investigation of the reef by scientists at Townsville’s Australian Institute of Marine Science found coral had been wiped out by intense tropical cyclones, a native species of starfish and coral bleaching. 

Researchers warned that while the World Heritage listed reef was a dynamic system — with coral cover rising and falling over time — if the mass die-off continued less than 25 per cent would exist in 2022. 

“The big concern going forward is that if nothing else changes than within 20 years the reef could be in a perilous state,” said institute senior scientist Peter Doherty. 

At 214 reef sites surveyed, the coral cover halved from 28 to 13.8 per cent between 1985 and 2012.

Two-thirds of the loss occurred since 1998. Only three of the 214 reef sites exhibited no impact. 

“Coral cover is the simplest index of reef health, and the health of the Great Barrier Reef has gone down dramatically,” said institute senior scientist Hugh Sweatman. 

“The coral provides shelter and food for thousands of organisms so you don’t just lose the corals themselves you lose the species that depend on them.” 

The coral damage was most pronounced in the central and southern regions of the 2000-kilometre reef, with the remote northern section remaining largely unaffected.

Tropical cyclones accounted for 48 per cent of the coral die-off across the entire reef, followed by outbreaks of the crown of thorns starfish, which was responsible for 42 per cent of the loss. Bleaching contributed to 10 per cent of loss. 

“You can dive on a coral reef one week when all you can see is living coral, each colony overlapping with its neighbours, but after the passage of a cyclone it looks like a cement road,” said Dr Doherty. 

Global warming models project increases in water temperatures will lead to more intense cyclones.

While crown of thorns starfish were a natural predator of coral — the adult animals feed on tiny polyps inside the coral skeleton — their impact over the past 25 years had been substantial. 

A large outbreak that started around Lizard Island in 1994, spread the length of the reef over 15 years.

Flood waters carrying fertilisers and other agricultural nutrients into the ocean were thought to increase the survival of crown of thorns larvae because the runoff encouraged the growth of algae eaten by the offspring.

 

“The frequency of crown of thorns outbreaks on the Great Barrier Reef has likely increased from one in every 50-80 years before European agricultural runoff, to the currently observed frequency of one in about every 15 years,” said the authors. 

Warmer waters were also responsible for coral-bleaching events, where the tiny organisms living inside the coral skeleton “bleached” and died with the rising temperatures. 

“The recent frequency and intensity of mass coral bleaching are of major concern, and are directly attributable to rising atmospheric greenhouse gases,” wrote the authors, whose study is published in the journal Proceedings of the National Academy of Sciences.

“Bleaching mortality will almost certainly increase in the GBR, given the upward trend in temperatures,” they said. 

While the state of the world’s longest reef system appeared bleak, it did have the ability to recover.

“What it needs is a decade or two to do it in,” said Dr Sweatman.

This too shall pass.

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10 thoughts on “The new normal (part 22): The Great Barrier Reef is dying

  1. Martin Lack says:

    I watched another programme in the Conspiracy Roar Trip series last night – this one being about people in the UK that believe the 7/7 bombings were an inside job…! As with the original programme about the 9/11 atrocity in the USA, I was left feeling very worried about the prognosis for humanity given the way suspicion of governent/authority leads people to embrace conspiracy theory…

    For F#ck’s sake, just exactly how much evidence do people need before they will accept that climate change is not a government conspiracy?

    • “The Accumulated Cyclone Energy dissipated by tropical cyclones worldwide this year (2012) is near-normal across the board from the Northern Hemisphere, and was below normal for the Southern Hemisphere during the last season (Fall 2011-Spring 2012). Globally, ACE is below normal for this year.”

      He only talks about it being down for the previous year. The graph however, http://wattsupwiththat.files.wordpress.com/2012/10/maue_hurricane_frequency.png

      looks pretty flat to me. If I was unscrupulous like deniers I could cherrypick and say that the first year of the graph, 1978, actually had 50% less major hurricanes than the latest data point in 2012 and about 20% less hurricanes overall, but I won’t do that because I have more integrity than that. The trendlines on that graph are consistent with many predictions that the storms will be less frequent but more severe. Thanks for the tip.

      But here’s the tip. If you actually read the report about the 50% decline on the GBR they talk about the interplay of the four main factors. The reef structure is compromised by crown of thorns starfish, run-off and bleaching so that when cyclones strike,more damage is done than might normally occur. Don’t forget also that Cyclone Larry in 2005 and Cyclone Yasi in 2011 were the two largest cyclones to strike the Queensland Coast in recent memory. Yasi inparticular was a massive system that devastated large areas of the reef.

  2. john byatt says:

    Comments so far read on QLD site, replies to story.

    EL NINO
    HOAX
    DO NOT TRUST SCIENTISTS
    VOODOO SCIENCE
    BEAT UP
    NATURAL
    REMEMBER DR BURROWS

    • john byatt says:

      The Dr burrows angle is that real science is being locked away if it does not conform to the agenda.

  3. Watching the Deniers says:

    Actually, they will focus on “its the cyclone’s stupid” failing to appreciate the interplay between different drivers. The levels of nitrogen run off is dangerous – and stupid.

    In 100 years time, lets rename the dead GBR “The Great Newman (Sea) Desert”.

    If readers haven’t been, then do go.

  4. Sammy Jankis says:

    Another line of attack will be that in some other part of the world a coral reef is doing alright.

  5. My predictions

    1. the deniers will focus on the 5% and say it is hardly “catastrophic”.
    2. they will point out that the crown of thorns starfish is native and therefore its ‘natural’
    3. they will rubbish Hansen and say there’s no evidence that storms are worse.

    All up they will refuse to look at the big picture and fail to acknowledge that the majority of the reef’s problem is due to poisonous land practices. I used to work in FNQ in a government department and I have intimate knowledge of the shortcomings in the reef rescue plan and the Qld government’s reef protection plan. DERM, the government department who supplies reef protection officers is a managerial shambles and a large number of the people on the ground are on temporary contracts which will most likely not be renewed by order of Campbell Newman. Banana growers who apply up to 400kg of nitrogen per acre on their farms each season are exempted from having runoff plans as are canegrowers with less than 70Ha of contiguous cane. It’s a joke and the reef is history. Go and see it while you can.

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