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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

Australian Academy of Sciences rebuts skeptics swindle.

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It would seem that no one who has any credibility supports the recent airing of the climate skeptic film, ‘The great global warming swindle’. Here is the press release from Australia’s most exalted science body. It is also worthwhile going to the specifics of the Academy’s rebuttal (www.science.org.au/reports/index.htm).

Thursday 12 June 2007 : Verdict remains the same: the CO2 is guilty

The Australian Academy of Science maintains the view that recent global warming is caused by unprecedented CO2 levels in the atmosphere, despite claims made in a recent documentary. Continue reading →

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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Swindled – an evening lost

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After putting the kids to bed, I got my mug of cocoa and sat down to watch The Great Climate Change Swindle. Let’s call it ‘Swindle’ because that is how I felt once it had rolled out across Australia.What I was rather disappointed by was the attempt to sell me, the average citizen, a series of thinly disguised half-truths about the lack of a linkage between carbon dioxide and global temperature, and then how the activity of that vicious orb in the sky was driving the climate.

The dulcet tones of Durkin waxed and waned, through the ‘facts’ and how dodgy scientists must be – I must have dozed off, but I seemed to come to as I was told that Margaret Thatcher had started the equivalent of Marxist, greenie plot called Climate Change so she could get into nuclear energy. Wow, I never knew!

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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 →

ABC & Lateline

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Thursday 12th July, 8.30pm – ABC television are showing the controversial documentary “The Great Global Warming Swindle“, written and directed by Martin Durkin followed by a Lateline analysis (10.30pm) interviewing Durkin and a range of scientists who oppose and support Durkin’s proposition. This will be essential viewing – originally shown in Britain by Channel 4 as ” Everything you’ve ever been told about Global Warming is probably untrue” (more).

Analysis of the “scientific facts” and social commentary to follow shortly from www.climateshifts.org and John Quiggin’s blog (www.johnquiggin.com) – watch this space. Meanwhile, take a look at two contrasting pieces published in The Australian newspaper yesterday (10th July)”:

“Sun not behind global warming”
– Leigh Dayton (10/07/07)		 “It’s good sense to avoid consensus on global warming”
– Bob Carter (10/07/07)
Updated: See Professor Ian Lowe’s detailed response in today’s Herald Sun (11/07/07):

“The Channel 4 film is indeed a great global warming swindle. It purports to show scientific evidence casting doubt on the conclusion that most of the recent climate change is due to human burning of fossil fuels. In fact, most of the “science” is either wrong or selective, so the film does not pose any real question about even the cautious conservative conclusions of the IPCC. If it is shown without an appropriate public health warning, it could give the misleading impression that the science is still uncertain and delay even further the urgently-needed concerted response..”

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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Climate change “hysteria” ?

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Interesting to read the latest anti climate change op-ed piece by Professor Bob Carter in the Courier Mail the other day.

Instead of contesting the tone of his argument, I will stick to what Professor Carter describes as the ‘salient facts’ with which he uses to show that climate change is nothing but “hysteria”:

The accepted global average temperature statistics used by the Intergovernmental Panel on Climate Change showed that no ground-based warming has occurred since 1998. Oddly, this eight-year-long temperature stasis has occurred despite an increase over the same period of 15 parts per million (or 4 percent) in atmospheric CO2.

Whilst this finding of the IPCC is an interesting point (see Graph a below), this fact alone does not disprove climate change: what is more misleading is what Professor Carter isn’t telling you.

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