Tag Archives: Coral Reefs

Comments on the decline of the Great Barrier Reef: Peter Garrett

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Below is an extract from The Age, with comments from Peter Garrett, the shadow minister for climate change, regarding the decline in coral cover on the GBR: (link to full article)

“The Great Barrier Reef is our greatest natural asset but the failure of the Howard government to introduce a comprehensive climate change plan is compounding its risk of extinction”

“The Queensland economy will be permanently damaged if we fail to deliver comprehensive climate change solutions that secure the reef’s future,” he said.

“With three quarters of the world’s coral reefs located in the Indo-Pacific and up to 60 per cent expected to be lost by 2030, our region is at the frontline of climate change.”

WWF: Reef or Rubble?

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From this morning’s Sydney Morning Herald

(Link to article, Link to WWF) :

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August 10th, 2007

AT LEAST $300 million needs to be spent urgently to clean up millions of tonnes of mud and chemical pollution pouring into the Great Barrier Reef every year, to boost the reef’s immunity to climate change, according to a new report from WWF.

The Federal Government had to act now to give the reef its best chance of avoiding future degradation, the environment group said. Its assessment comes before the release of a federal report widely believed to show a dramatic increase in pollution levels in Queensland rivers and creeks feeding into the reef.

Reefs worldwide are under threat. A University of North Carolina study published on Wednesday said large-scale degradation of the world’s coral reefs was much worse than previously thought. Over the past two decades, coral had disappeared at five times the rate of the planet’s rainforests, it said.

WWF said more than 90 per cent of the Great Barrier Reef’s pollution came from soil, hazardous chemicals and pesticides washing off farms and sugarcane plantations.

“We are creating a milkshake in the reef that is feeding the larvae of crown-of-thorns starfish,” said Nick Heath, of WWF-Australia.

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Indo-Pacific Coral Decline

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A new study released today by Bruno & Selig in PLoS Biology shows some very interesting trends in coral decline in the Indo-Pacific. In a nutshell:

  • Average coral cover is lower than expected (22.1%, 2003).
  • Coral cover is surprisingly uniform across regions.
  • Coral cover on the GBR (often considered one of the best managed reefs in the world) is no higher than other regions (e.g. Phillipines).
  • Although there is a lack of historical baselines, regional coral cover is at least 20% below historical records.
  • Indo-pacific coral cover declined from 42.5% in the early 1980’s to 22.1% in 2003.
  • This equates to an average rate of decline of 1% per year (approximately 1500km2 per year).
  • Between 1995 – 2003 coral cover declined by 14% (3168km2 per year).
  • In 2003, only 4% of surveyed reefs had high coral cover (>50%), and only 2% of reefs had very high cover (>60%).
  • Regional scale decline of the Great Barrier Reef occured several decades earlier than often assumed (<1970).
  • Coral decline in some sub-regions of the Indo-Pacific began during the 1960’s – 1970’s.
  • Localised anthropogenic impacts have caused coral losses (e.g. sedimentation, destructive fishing practices).

Based upon 6001 surveys of 2667 reefs in the Indo-Pacific, the report makes for sobering reading. I have decided to add a “sub-section” to Climate Shifts entitled “Science Review” to encourage a weekly debate upon key scientific issues such as this – head over to Science Review to read more about the study and comment / debate the major findings.

The “GBR Swindle” revisited – response to Peter Ridd

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It seems that “The Great Barrier Reef Swindle” and my subsequent response generated a fair amount of debate throughout the blog world and the scientific community. Dr Ridd has posted his response to the my comments regarding the science behind the response here, and in keeping with the science and debate, see my response below.

Before I go into detail on this, attached is one of the paired photographs from the inshore reefs in Bowen, Queensland detailing local scale changes on the Great Barrier Reef during the 20th century (photographs speak louder than words):

 

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Oh dear, here comes another expert on the Reef.

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peter_ridd.jpgThis time it is Dr. Peter Ridd (an expert in marine physics) who is claiming that there is an even greater swindle going on with respect to the Great Barrier Reef. The title of Dr. Ridd’s opinion piece dated 19th of July 2007, says it all – “The Great Barrier Reef Swindle”.

His thesis? Hundreds of scientists who work on the Great Barrier Reef are all also involved in the same sort of cover-up and conspiracy that we were told about in the Great Climate Change Swindle! Big news indeed.

Yes, same story, scientists make up the doom and gloom tale so that they can get lots of research money from unsuspecting agencies and donors.

Sound familiar? Jennifer Marohasy has written similar things in the past (and she loves his opinion piece!). Oh, and guess who Dr. Peter Ridd reports to in his role as Science Coordinator to the newly created” Australian Environment Foundation“? Continue reading →

Photographs from the coldwater bleaching event (17/07)

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An update with recent photographs from the 2007 cold-water bleaching event at Heron Island (from Dr Selina Ward, a researcher and lecturer at the University of Queensland). At high tide, the bleaching (loss of the symbiotic algae) is clearly evident in the branching coral from the submerged reef flat (left); at low tide the exposure of massive corals (center) and branching corals (right) results in significant levels of mortality. See my post below (“Winter bleaching again on the southern Great Barrier Reef”) for further comment.

 

Winter bleaching again on the southern Great Barrier Reef.

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Unusually cold weather on the southern Great Barrier Reef has triggered localized bleaching on the reef crest at Heron Island. Low tide, strong winds and unusually cold wintry weather in July 2007 has caused the top few centimeters of coral in the intertidal sections of the reef to bleach. Cold bleaching has been reported before at Heron Island by others during 2003, and is very similar to bleaching that occurs when water gets too warm.

So, is this event a sign of global climate change?

I don’t think we have enough evidence to say this right now. Some models, however, suggest that the southern Great Barrier Reef may experience colder winters with a weakening if the south Pacific gyre, which runs down the east coast of Australia and normally pushes warm water southward. Certainly, colder years tend to follow strong El Nino (warm) years. So far we have seen winter bleaching on the southern Great Barrier Reef in 1999, 2003 and now in 2007. In the three cases, the preceding years 1998, 2002 and 2006 were very warm years and saw extensive coral bleaching on the southern Great Barrier Reef.

Perhaps a passing meteorologist could work this one out for us. If there is a connection to climate change, then we might need to consider the effect of corals stressed out in summer that are then stressed again in the following winter.

Cold water Bleaching at Heron Island in July 2003 cold-water-bleaching.jpg

Barrier Reef ‘can adapt’ to warmer times

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  • Updated (13/07) – See Dr van Oppen’s response below.

So said a headline in The Australian this morning.

Based on a study coming from the lab of Dr Madeleine van Oppen, the article made the amazing leap from a study in which scientists have found that many corals have several varieties of symbionts to saying that the Great Barrier Reef can adapt to climate change.

And it wasn’t the papers fault (which was published in the peer-reviewed journal, Coral Reefs – doi 10.1007/s00338-007-0244-8).  This is actually what the senior investigator on the paper, Dr van Oppen, said “”This flexibility discovered in our research is important in understanding the past evolutionary success of these coral species and their future survival capacity in the face of changing climate,”

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Further commentary on the “Swindle”

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From a colleague and good friend of mine, Dr. Paul Marshall, (Acting Director – Climate Change, Great Barrier Marine Park Authority):

“It is extremely frustrating to see the inordinate influence these so-called climate skeptics have on the broader community’s perception of climate change. Uncertainty and doubt about the reality and causes of climate change can no longer be justified in the face of the conclusions of the Intergovernmental Panel on Climate Change. The IPCC’s findings represent the consensus of thousands of the world’s leading experts, developed through a highly scrutinised and transparent process, and adopted by the majority of the world’s governments, including Australia and the USA. None of us want climate change to be real, and we certainly don’t want to think that we might be the cause of it. But denial and self-delusion are luxuries that we cannot afford. Ecosystems are already beginning to decline and people are starting to suffer due to extremes in environmental conditions that will only get worse with climate change. Anyone who has seen the effects that abnormally high water temperatures have on coral reefs can not sit back and hope that climate change isn’t happening, or that it will simply fix itself. Mass coral bleaching has already caused lasting damage to sections of the Great Barrier Reef. While we have been lucky compared to many other reef areas (some of which lost 50-90% of their corals in 1998 alone) the Great Barrier Reef Marine Park Authority is taking the threat of climate change very seriously. If we have any hope of helping coral reefs survive climate change, it will require a concerted and dedicated effort to reduce the effects that our activities are having on the world’s climate.” Continue reading →

Hurricanes and coral bleaching

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A recent paper published in the Proceedings of the National Academy of Science suggests that hurricanes may well be the ‘unlikely saviours of coral reefs’ (link to the New Scientist article). In short, researchers from the Caribbean determined that on average, hurricanes will actively cool sea temperatures by 1.5°C for upto 10 days. Since hurricanes occur during the hot summer months, this reduction in sea temperatures acts as a lifeline for thermally stressed and bleached corals within the region.

The authors conclude that “…severe bleaching events can have dramatic, long lasting impacts on the structure and function of coral reefs, and the cooling benefit of a hurricane can have substantial mitigative effects”. Parallels can be drawn between hurricanes in the Caribbean region and cyclone events on the Great Barrier Reef.

Back in the summer of 2006, substantial warming of the oceans on the GBR threatened yet another bleaching event of a magnitude of 1998 and 2002. Fortunately for the reef, the category 5 cyclone Larry produced significant cooling effects across the length of the GBR resulting in minimal coral bleaching – acting as an ‘unlikely savior”. At the time, I was the subject of this diatribe from the ‘journalist’ Andrew Bolt, published in the Herald Sun:

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