This 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“? Yes, none other than its director, Dr. Jennifer Marohasy, also Environment Director to the right wing think tank, the Institute of Public Affairs (IPA). Jennifer also does not believe that the Murray Darling River system is a mess or that carbon dioxide is such a big deal either!
Okay – some much for the fun. Let’s get down to the facts.
What are Dr Ridd’s key messages? They are (with my response underneath):
1. “corals are more tolerant to rising waters temperatures than first thought by most people..” This is a reference to a paper published last week by the Australian Institute of Marine sciences. I have read the paper, though it seems that Peter has not.
The message to Peter is that there is a big difference between a newspaper article and a peer-reviewed publication in a scientific journal. Peter links us from his text to the Australian and … Voilà … that is what the headlines say.
The more diligent of us of course went to the paper and discovered that it didn’t say what the headline (or Piers Ackerman) said it said. In fact, when we profiled it at our blog, Dr. Madeleine van Oppen, the lead author, felt compelled to put a correction on the record and said “The article in today’s Australian is a miss-representation of our work.” Pretty final don’t you think?
Yes, Peter, you will need to go to the original sources next time. That is what other scientists do.
2. ‘Corals are cockroaches’
When I first read this statement, I thought, oh dear, Peter’s lack of training in basic biology has let him down again!” No – I wont be snide, I did actually understand what he was trying to say – and I actually agree with him. Corals are like cockroaches in that they’re extremely difficult to make go extinct. Corals are able to reproduce on their own (asexually) and have some of the largest biogeographical ranges of any organism. This means that they can hang out for long periods as a single individual and still grow and ‘reproduce’ without needing another individual. Their large ranges mean that they are likely to have somewhere, even in a catastrophe, to find shelter and survive. Not that it makes them invincible but it probably increases the odds against their extinction.
What is the point here?
Peter is telling us that we don’t have to worry about the extinction of corals. I also think we don’t have to worry about the extinction of corals. But this isn’t the issue.
The issue is that corals may survive in geological time but may dwindle so that they become very, very rare. That means they won’t be building the reefs that house the thousands of species. Those thousands of species underpin a $5 billion economic nest egg given to us each year from Great Barrier Reef associated fishing and tourism.
Corals can survive catastrophes and have as demonstrated in the geological record. But what Peter doesn’t tell you is that corals are not common during these catastrophes and that it takes thousands if not millions of years the corals to rebuild the coral reefs off to a catastrophe. Trying telling our friends in the tourism industry that they will have to do without corals for 10 let alone 1,000 years!
3. “Corals like it hot”
And so do we. But if you push the temperatures up are too high for us (beyond our coping range) we have big problems. The extraordinary heat wave in Paris in 2003, when over 14,000 people died, is a case in point.
Corals have certainly adapted to the temperature of the local environment. At each of these locations, I will bleach and potentially die when they go beyond the local thermal threshold. Off Sydney, corals will bleach when the water hits 26°C. Off Gladstone, on the southern Great Barrier Reef, I will begin to bleach at 29°C. Off Townsville, they will bleach at 30°C.
Raise the temperature by a further 2°C at each of those locations, however, and the corals will die. Yes, each has adapted (over hundreds if not thousands of years) to the local temperature. But the issue here is not adaptation. It is the rate at which corals can adapt relative than the rate of temperature change.
What Peter Ridd doesn’t tell us is that the current rates of temperature change are at least a hundred times greater than the Ice Age transitions (the period in which the Earth went from being told with lots of on ice to warm like it is today). Yes, at least hundred times as fast. Go get the Vostok Ice core data and calculate it for yourself.
Given that fact, it is perhaps no wonder that mass mortalities of corals are on the rise. In 1998, there was a 16% decrease in the number of corals survey by the multinational Global Coral Reef Monitoring Network (GCRMN). Peter Ridd states that we didn’t lose many corals from the Great Barrier Reef in 1998 or 2002.
Another furphy. Let’s have a look at the actual numbers.
The official figure from the Great Barrier Reef Marine Park Authority was that around about 5% of the corals on the Great Barrier Reef died (“severely damaged”) in each event (1998, 2002). Doesn’t sound like much until you consider the size of the Great Barrier Reef? If one does the calculation, there are probably at least 40,000 km² of corals dominated communities on the Great Barrier Reef. If you use this number as a minimal estimate (and it probably is) then the loss of 5% of 40,000 km² of corals, represents a loss of 2000 km² of coral communities! If you can live with that happening every 3-4 years, Peter, then you’re a better man than I!
But you are right, it is not like what happened in the Western Indian Ocean, on the reefs of the Okinawa, or in Palau or off Scott reef in Western Australia, where between 50 and 90% of the corals disappeared from reefs during 1998. The problem is that the best science (published in peer-reviewed journals) indicates that the frequency of bleaching events is likely to increase in the coming decades. Do we have any credible data to say that we should NOT heed these projections? To my knowledge and expertise, no.
4. ‘Climate change is happened before and has been worse’.
This is a common line from some who focus on long time scales – namely the geological record, which has a time scale that goes well beyond that of the ecological (today). Some (only only a few like Bob Carter and Peter Ridd actually) say that “it’s has all happened before, so why are we worried that it happening today”.
There is a small but critical detail missing from this type of interpretation and conclusion. And that is that the sudden retreat of the glaze or the flooding of coastal Australia at the end of the last Ice Age occurred at rates that were at least a hundred times smaller than the current rate of climate change and what we’ll be seeing in the future.
That is, an early Australian would have to have lived to 5000 years old (not 50) to see the sorts of changes that we are likely to see in the next 50 years. It basically says that early Australians probably only had the vaguest notions that the climate was changing if they had any notions at all. Change was nothing like recent decades or that that is projected.
5. ‘We have been swindled’
At this point, Peter, after trundling through half-facts and half-truths comes to his final section. Here, he lists why he thinks we have been swindled. The first reason given is that “some very bad science is involved”. I have already tackled this above – I think it is a bit rich from a fellow who has not published his objections in a peer-reviewed science journal and has blundered with the facts and science above. Scientists constantly criticize scientific ideas through the vehicle of anonymous peer-review. That is all part of scientific progress. Why hasn’t Peter used this vehicle before?
Secondly, Peter indicates that the examination of the issues for the Great Barrier Reef is dominated by the biological science community which should (but doesn’t according to Dr Ridd) make reference more to the geological history of corals. It is interesting that Dr Ridd has glossed over the work on two of the most prolific authors on the Reef, John Pandolfi (University of Queensland) and John (Charlie) Veron (ex-AIMS now University of Queensland) who have produced a vast literature and trained generations of scientists with the methodology which is constantly calling on our understanding of the geological time frame in which corals and coral reefs have evolved. This sounds like the confusion that Dr Ridd had with thinking that we are worried most about the extinction of corals when we are not.
The last point that Dr Ridd makes is the old argument that scientists are feathering their nests and that they have to mention the “CC” word to get funded. This is a tired old conspiracy theory — the peer review system works in a way that would make conspiracy very extremely difficult. Try running a committee to obtain consensus out of 10 let alone 100 scientists! Granting success works on originality, tractability and having the goods (a solid track record in the peer-reviewed literature). In fact, if you had the track record, and had solidly based evidence that climate change was a myth, then you would probably become one of the most well funded scientists of all time!
In his conclusion, Dr Peter Ridd Peter states that it would be good to have the disgraced director Martin Durkin (producer of “The Great Climate Change Swindle”) come over to Australia and do make “The Great Barrier Reef Swindle”.
I suppose that choosing a producer who faked data, misquoted people and chose to use data selectively is the right man for your job, Peter.
But he isn’t my Sir David Attenborough!
I agree 100% with OHG
I agree with Ove and would add that, as is well known, climate change is just one, albeit, a major one, of the impacts facing corals and the reefs they build. In respect of risk of extinction, although many coral species are widely distributed, others are not. Even among the widely distributed species, some are, as far as is known, uncommon or rare through much of their distribution ranges, and are only common in rel. small areas of preferred habitat. Thus their major reproductive stocks are not necessarily as widespread as their distribution range implies. The growing combination of synergistic impacts (temperature change, diseases, COTS predation, destructive fishing etc. etc.) is likely pushing some of the latter towards extinction, with major reductions in their population sizes over past decades. Many such species may ‘hold on’ in much reduced abundance over coming decades – centuries, others may not.
It seems that corals shouldn’t be lumped into one generic basket. I think your expert comment is a useful reminder, Lyndon, that impacts may look very different from one species to another. Hence saying that ‘corals’ have and will survive is a vast over simplification.
I agree with Ove…we are seeing changes in the Coral Reefs. I am working at a high-latitude coral community in Japan. My colleagues who are working on recruitment patterns in these communities have observed every year that there is increased occurrence of coral eggs coming from tropical areas through Kuroshio current and settling here..Moreover, in the past 10 years, I see summer and winter average sea temperatures fluctuating a lot. At present the corals here are adapted to the local temperature (as Ove points out clearly) but if the upper temperature shifts, then the consequences can be bad…at present the occurence of COTS, Drupella, algal cover..all is balanced, but i fear that if there is shift in the temperature, all these stress combined with temperature stress will make corals here susceptible beyond their limits..
I find the general view that all corals are widespread and buffered from extinction (i.e. cockroaches) very hard to swallow. The empirical evidence of corals with restricted ranges, small population sizes, high susceptibility to impacts, and low rates of gene flow is mounting and speaks mountains for the threatened status of coral biodiversity. I challenge the sceptics to re-visit their argument after they dive on some of the many devastated reefs either locally or worldwide or visit isolated reefs and see for themselves the absence of mature adults and lack of juvenile colonies and in some cases the absence of entire genera of corals that would otherwise be expected to be present. Assuming coral biodiversity on devastated reefs will miraculously recover by an abundant supply of recruits in a highly connected global reef system is false and outdated.
I work in the Arabian Seas and this year sea surface temperatures off Muscat hit 33 degrees C on 11 July. http://www.osdpd.noaa.gov/PSB/EPS/CB_indices/oman0map.htm NOAA are considering re-drawing their graph to extend the temperature axis to accommodate temperatures as high as this. This is also a year when Muscat was hit by a cyclone, an event with a return time of over 100 yrs. Its just possible these are isolated incidents, but when you consider the pattern around the world as well as the peer reviewed literature they fit the pattern predicted by IPCC as consequences of climate change.
It seems to me that an investigation into Australian Environment Foundation’s own sources of funding might be revealing. Are they simply in denial or do they have a vested interest in spreading negative propaganda about climate change, I wonder.
For time series of SSTs off Muscat:
http://coralreefwatch.noaa.gov/satellite/current/sst_series_omanmuscat_cur.html
Further to Lyndon’s good point, I think the media (and some simple scientists it seems!) can’t grasp the difference between species extinction (as in Dodo, Sabre-Tooth Tiger etc) and ecological extinction (as in the system is too broke to work any more). One remaining oak tree in a clear-felled mud-scape is not species extinction of the oak, but the forest doesnt do foresty things any more.
I have recently returned (again) from a very heat stressed region of the coral reef world – Arabian/Persian Gulf – and dived for many hours on once rich reefs. I saw a live coral at intervals of perhaps 20 or 50 metres apart, the rest being dead. That is zero coral cover to the nearest whole number, but it is still not species-extinct. You would need to measure cover to about 0.0001% to register a positive number there. But then, to how many decimal places do we need to measure ‘dead’? Answer: to many, if you are looking to confirm species extinction, but none at all if you want to determine whether you still have a reef.
They dont have reefs any more in the sites I worked, but they do have the odd coral still. The reefs, are as dead as Monty Python’s parrot: eroding, not accreting, bio-deficient, not biodiverse, unproductive not productive, just plain dead, to use a shorthand. The existence of a tough Cyphastrea here and there does not make them living.
Ironically, these are the reefs (or the area anyway) which Kinsman observed in 1964 (Nature 202:1280-1282) to suggest that corals had a greater range of tolerance to heat and salinity than we previously thought!
Lumping into one basket:
Maybe if we clarify what type of corals and algae will survive anthropogenically induced global warming this may help matters? The truth of the matter is that only a very few species of corals will be able to survive this underwater holocaust, and my appologies for using strong terminology,however, this is putting it lightly. The shift in reef species will be dire and replaced with macroalgae. We can debate this all year, however, if we (as scientists) dont address what is trapping this heat and let the political parties know that only DRASTIC reduction (not this 30% Kyoto morsal) the CO2 will continue to rise and it will come to a point when……hey what am I saying…hello WE ARE AT THE POINT!! Enough!
Just to add full support for Oves comment and encouragement to all the scientists trying to save the reefs and conserve the sea.
Keep up the good work – The world needs you!
The science speaks – thank you all for your input and observations (from the Arabian Gulf to Japan) – Charles highlighted a very important point regarding the difference between “extinct” and “functionally extinct” in ecosystems that often seems to be missed by the marine physicists (Ridd) and geologists (Carter) of this world.
James – interesting point: how do you propose we address these shifts in community structure at a functional level? Moreover, how do we as scientists best communicate this?
Following on from James and Ove, in regard to communicating the increasingly dire situation to the wider global audience, Charles Sheppard’s point re ‘functionally-extinct’ could be a very powerful message for media / documentaries etc. I do think this communication aspect has improved greatly in the past couple of years. Obviously IPCC, Al Gore, the scientific consensus in the major journals and across the science ‘establishment’at national and intl. levels, and the wider media attention generated there, have all helped. However, some of our national governments are now lagging behind, for various reasons, and it is really up to us as citizens to make our views clear at forthcoming elections. In this respect, and as was mentioned some time ago elsewhere, we do need more ‘champions’ of coral reefs, and I for one really applaud Ove, among many others, for getting the message out there.
From Caspar Henderson: “Useful and enlightening discussion of the possible consequences of manmade climate change and other human impacts on the environment sometimes gets side-tracked in reports, often in the media, in which evidence and analysis are not properly represented. A recent example in the case of coral reefs seems to be “”The Great Barrier Reef Swindle” (see, for example, a commentary on this at climateshifts.org: “Oh dear, here comes another expert on the Reef” 22 July 07).
Extreme, often irrational skepticism about the likely impacts of climate change can be relatively easy to refute, as can arguments made in bad faith; but do more subtle, nuanced differences loose out in the heat of a slanging match, and if so what are they are how much do they matter? So, in the case of coral reefs, could some assemblages recover (on a relatively short time scale: years, decades) from higher temperature shocks than is sometimes thought? If so, how far? Did the IPCC 4AR WG2 actually accept (as the language in the final draft seems to suggest) a possibility that corals could adapt to 3 C rise or even more (see:
http://coralstory.blogspot.com/2007/04/ipcc-drafts.html)?”
“Corals like it hot”
You really don’t even need to go into the paeleo record to refute, or even bleaching… every study I’ve seen shows loss of tissue biomass/thickness during the hotter season.
I thank Prof HG for his comments regarding my article in OnlineOpinion http://www.onlineopinion.com.au/view.asp?article=6134.
The point numbers below refer to Prof HG’s original points however I should first add that I do not think, and certainly did not say that there is some cover up regarding the health of the GBR. There is simply a scientific disagreement.
1 “corals are more tolerant to rising waters temperatures than first thought by most people”
Prof HG claims I misrepresented the science in a paper by Dr Madeleine van Oppen and Jos Mieog. However the AIMS media release seems to agree with my analysis. I quote
“The potential for this hidden back-up type (algae) to step in and provide nutrition to coral during heat stress is far greater than currently thought,” Mr Mieog added.
This is also not the first time that evidence been gathered that indicate that corals can respond relatively quickly to temperature changes by taking on different strains of zooxanthelae.
2 Corals and Cockroaches
Prof HG misrepresents some of my comments regarding canaries and cockroaches. The point is that corals are not delicate organisms and that the analogy often used that corals are the world’s canary is misleading. It is however doubtless a very effect publicity tool to use this analogy.
3 Some like it hot.
My article was about the GBR not about other coral reefs systems around the world. As I said previously most of the GBR did not bleach and most that did has fully recovered. There is also little doubt that the growth rate of massive corals has increased in the last century. I think it highly unlikely that the hard cutoffs threshold for bleaching that Prof HG talks of are genuine. An organism that has seen so much climate change over the eons is unlikely to have a weakness like a not adaptive thermal threshold.
4 Climates have changed before.
Prof HG states correctly that previous changes in climate are far slower than what we may see if you believe the extreme IPCC predictions. However the rates of climate change we have seen over the last 200 years is certainly not outside the bounds of what is found in the geological record (and yet we still see bleaching). Absolute temperatures are also probably not outside the bounds of what the GBR has seen in the last 1000 years (viz Medieval Warm Period). The Holocene climatic optimum was also most likely significantly warmer than today. That means that the bleaching event we have seen have almost certainly occurred in the recent past and may be nothing unusual.
It is wrong to state that Aborigines probably did not even notice that things were changing when the coast retreated up to 100 km in a few thousand years and the sea level was rising by 10 mm per year. The change was profound enough for the memory to be etched into their culture through traditional stories. And there are Noah’s Ark flood stories in almost all cultures. The last deglaciation was a climate change of monumental proportions and a time when the GBR was being born. The change the GBR then experienced is far greater than what we have seen over the last 100 years.
It all boils down to whether the IPCC is correct with its extreme prediction of perhaps 6 degree climate change. A couple of degrees of warming will be neither here nor there to the corals. 6 degrees is a major problem. However I guarantee you that changes in the GBR will be the least of our concerns under that scenario. Worry more about the land ecosystems and shifting population. The GBR might be damaged under a 6 degree rise in 100 years, but the rest of the world will be annihilated.
5 Have we been swindled
There is much to respond to here but I will confine myself to the question that Prof HG asks of why I do not raise these issues in the literature, rather than in newspapers and weblogs. In fact I try to get my views in the scientific literature but sometimes it is very hard to get comments published. For example some time ago I attempted to get a comment on a paper by Pandolfi et al 2003 in Science which claimed that the GBR was about 1/3rd of the way the ecological extinction. I believe that paper has 4 fundamental errors and I tried on 3 occasions without success to get Science to publish a comment. After this failure I wrote a full paper outlining the problems with the methodology. I submitted this paper first to L and O and then to Corals Reefs and both rejected the paper without even accepting it into the review process. Fortunatley I have since found a journal to publish this work but it is unlikely to one that people on this group will read (Energy and Environment)
So I can assure you that being the heretic does not make publication easy and I do not regret using any outlet at my disposal to get the message across.
Finally, nothing that I have read in Prof HG’s article makes me change my mind that the GBR is probably the most intact and least impacted ecosystem on earth with the exception of Antarctica. Its present superlative condition means that it will cope with climate change, whether it be natural or otherwise, far better than the devastated ecosystems on the land. A moderate warming combined with sealevel rise will also cause an explosion of coral on reef flats so it seems to me more likely that we will see more coral in the future, at least on the GBR. I am also still convinced that there has been massive exaggeration about the supposed state of the GBR and that this ought to cease forthwith. But go for your life and try and save the massively impacted reefs around the world. I am with you completely on that one.
Peter Ridd
Physics,JCU
Pandolfi, J.M., Bradbury, R.H., Sala, E., Hughes, T.P., Bjorndal, K.A., Cooke, R.G., McArdle, D., McClenachan, L., Newman, M.J.H., Paredes, G., Warner, R.R., Jackson, J.B.C., 2003 . Global trajectories of the long-term decline of coral reef ecosystems. Science, 301: 955-958.
In response to Charles Sheppard’s comments on the fate of Arabian Gulf coral communities. He is absolutely right in pointing out that coral reef structures are effectively a thing of the past within the Arabian Gulf with patchy un-diverse (generally
Once again I see a journalist getting it wrong when it comes to coral reefs: hardly surprising as editors want sexy headlines and simple to grasp news stories. As an author and journalist who tries to get it right may I make a plea? If coral scientists want us to ‘get it right’ they need to simplify the message and not get caught up in the minutiae of the biological debate. This recommendation goes against ‘good science’ and of course I understand that coral ecology cannot be reduced to a simple sound bite. And when dealing with the press it is worth remembering that when you ‘sup with devil you risk getting burnt’. Having said that – there seems to be only one message: coral reefs are dying at a swifter rate and in more places than we have ever seen before. Without reefs, coastal erosion, rising sea levels etc will worsen – fish and invertebrate populations and thence human populations will suffer untold consequences and death. DEATH – that’s a word journalists understand. MONEY is another one.
As far as I recall, it was coral scientists that first reached virtual unanimity about the anthropogenic causes of coral reef degradation in the Indian Ocean back in 2000 (CORDIO status report Eds. Souter/Obura/Linden) – long before the world sat up and took notice of the Stern report? But since then you’ve been sidelined by the movers and shakers of the carbon-offsetting lobby who are doing well financially and in PR terms out of global warming. What I’m advocating is a more aggressive stance when you talk to journalists – don’t keep qualifying your arguments and don’t keep disagreeing about what the definition of ‘reef death’ might be. And use words like ‘apocalyptic’. If that’s too unscientific then maybe the argument is best left confined to the science journals? But how about this: if the global sea temperature rises are not going to be reversed any time soon then why not start speaking out about the other stuff that mankind is doing to the coral? I have lost count of the number of small island states I have visited in the past ten years where rampant and insensitive coastal development has been the ‘straw that broke the camels back’ for nearby reefs. And yet, for fear of peer ridicule or political embarassment the scientists sit back and won’t get drawn into saying one simple thing: ‘this hotel/condo/golf course will kill the reef. you are making a mistake. stop it now’.
You (scientists) are dealing with a very complex ecosystem, and there is much more work to be done – but very soon, at the local level, there will hardly be any function reef ecosystems on which you will be able to carry out your work. It’s time to get off the fence – and when you talk to journalists keep it simple. DEAD simple. Respectfully, tim ecott
Dear Ove and the list; The way to address or communicate the severity behind fossil-fuel induced global warming is to first agree (as scientists) on an HONEST estimate for carbon reduction %%…..The Keyoto Protocol, we all know is tooth-less and not nearly enough to make a difference and reverse the current trends. We as scientists know that the “magic number” is hovering around 60% reduction.
What do the rest of you think?
Addressing “community shifts and structure”; this depends on how some of the coral scientists feel about algal dominated reefs once the delecate spp of corals are gone due to heat stroke. From some of the gut wrenching debates I have engaged in on the coral list server, it still appears as if there is a dominant group of scientists out there that think high levels of nutrients are ok for reefs and that if we increase herbivores that will reverse the problems. Once these heat stroked corals are dead, they will be quickly colonized with macroalgae due to humans fertilizing the sea to death (stole that one from S. Nixon). Conclusion: agree on a magic number for CO2 reduction and agree on the critical threshold number (%%) for N&P in a functional reef system.
Please note that this is a repeat of a response that I put on this blog a few days ago and which had been removed
I thank Prof HG for his comments regarding my article in OnlineOpinion http://www.onlineopinion.com.au/view.asp?article=6134.
The point numbers below refer to Prof HG’s original points however I should first add that I do not think, and certainly did not say that there is some cover up regarding the health of the GBR. There is simply a scientific disagreement.
1 “corals are more tolerant to rising waters temperatures than first thought by most people”
Prof HG claims I misrepresented the science in a paper by Dr Madeleine van Oppen and Jos Mieog. However the AIMS media release seems to agree with my analysis. I quote
“The potential for this hidden back-up type (algae) to step in and provide nutrition to coral during heat stress is far greater than currently thought,” Mr Mieog added.
This is also not the first time that evidence been gathered that indicate that corals can respond relatively quickly to temperature changes by taking on different strains of zooxanthelae.
2 Corals and Cockroaches
Prof HG misrepresents some of my comments regarding canaries and cockroaches. The point is that corals are not delicate organisms and that the analogy often used that corals are the world’s canary is misleading. It is however doubtless a very effect publicity tool to use this analogy.
3 Some like it hot.
My article was about the GBR not about other coral reefs systems around the world. As I said previously most of the GBR did not bleach and most that did has fully recovered. There is also little doubt that the growth rate of massive corals has increased in the last century. I think it highly unlikely that the hard cutoffs threshold for bleaching that Prof HG talks of are genuine. An organism that has seen so much climate change over the eons is unlikely to have a weakness like a not adaptive thermal threshold.
4 Climates have changed before.
Prof HG states correctly that previous changes in climate are far slower than what we may see if you believe the extreme IPCC predictions. However the rates of climate change we have seen over the last 200 years is certainly not outside the bounds of what is found in the geological record (and yet we still see bleaching). Absolute temperatures are also probably not outside the bounds of what the GBR has seen in the last 1000 years (viz Medieval Warm Period). The Holocene climatic optimum was also most likely significantly warmer than today. That means that the bleaching event we have seen have almost certainly occurred in the recent past and may be nothing unusual.
It is wrong to state that Aborigines probably did not even notice that things were changing when the coast retreated up to 100 km in a few thousand years and the sea level was rising by 10 mm per year. The change was profound enough for the memory to be etched into their culture through traditional stories. And there are Noah’s Ark flood stories in almost all cultures. The last deglaciation was a climate change of monumental proportions and a time when the GBR was being born. The change the GBR then experienced is far greater than what we have seen over the last 100 years.
It all boils down to whether the IPCC is correct with its extreme prediction of perhaps 6 degree climate change. A couple of degrees of warming will be neither here nor there to the corals. 6 degrees is a major problem. However I guarantee you that changes in the GBR will be the least of our concerns under that scenario. Worry more about the land ecosystems and shifting population. The GBR might be damaged under a 6 degree rise in 100 years, but the rest of the world will be annihilated.
5 Have we been swindled
There is much to respond to here but I will confine myself to the question that Prof HG asks of why I do not raise these issues in the literature, rather than in newspapers and weblogs. In fact I try to get my views in the scientific literature but sometimes it is very hard to get comments published. For example some time ago I attempted to get a comment on a paper by Pandolfi et al 2003 in Science which claimed that the GBR was about 1/3rd of the way the ecological extinction. I believe that paper has 4 fundamental errors and I tried on 3 occasions without success to get Science to publish a comment. After this failure I wrote a full paper outlining the problems with the methodology. I submitted this paper first to L and O and then to Corals Reefs and both rejected the paper without even accepting it into the review process. Fortunatley I have since found a journal to publish this work but it is unlikely to one that people on this group will read (Energy and Environment)
So I can assure you that being the heretic does not make publication easy and I do not regret using any outlet at my disposal to get the message across.
Finally, nothing that I have read in Prof HG’s article makes me change my mind that the GBR is probably the most intact and least impacted ecosystem on earth with the exception of Antarctica. Its present superlative condition means that it will cope with climate change, whether it be natural or otherwise, far better than the devastated ecosystems on the land. A moderate warming combined with sealevel rise will also cause an explosion of coral on reef flats so it seems to me more likely that we will see more coral in the future, at least on the GBR. I am also still convinced that there has been massive exaggeration about the supposed state of the GBR and that this ought to cease forthwith. But go for your life and try and save the massively impacted reefs around the world. I am with you completely on that one.
Peter Ridd
Physics,JCU
Pandolfi, J.M., Bradbury, R.H., Sala, E., Hughes, T.P., Bjorndal, K.A., Cooke, R.G., McArdle, D., McClenachan, L., Newman, M.J.H., Paredes, G., Warner, R.R., Jackson, J.B.C., 2003 . Global trajectories of the long-term decline of coral reef ecosystems. Science, 301: 955-958.
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