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Coral will dissolve if CO2 emissions don’t change

The world’s coral reefs will quickly dissolve if greenhouse gas emissions continue on current trends, a new simulation has…

Coral reefs under the business-as-usual-emission scenario, will quickly decalcify and dissolve. prilfish

The world’s coral reefs will quickly dissolve if greenhouse gas emissions continue on current trends, a new simulation has found.

Greenhouse gases cause the ocean to become warmer and more acidic, which bleaches and kills coral reefs, as well as the underwater ecosystems that form around them.

The new study, led by researchers from the University of Queensland and published in the journal PNAS, found that even modest increases in ocean temperature and acidity would kill off coral and increase the dissolution of their skeletons once they are dead.

“We discovered that coral reefs under the business-as-usual-emission scenario, the one we are on, show high rates of decalcification,” said lead author of the study, Associate Professor Sophie Dove from UQ’s School of Biological Sciences.

“Essentially, dissolving before our eyes over a few months.”

The study involved controlling the temperature and amount of CO2 in water that was home to a section of coral reef at UQ’s Heron Island research centre.

Study co-author Professor Ove Hoegh-Guldberg, director the University of Queensland’s Global Change Institute, said the study showed “that coral reefs are under even greater threat from ocean warming and acidification than we first thought.”

“This sounds gloomy but our study also emphasises the fact that there is time and that a small amount of effort today can have a huge impact on what happens in the future,” he said.

Zoe Richards, Coral Biodiversity Researcher at the Western Australian Museum, said the new study was ambitious and allowed researchers to study coral reefs in systems that more closely replicate the natural environment.

“The results suggest that in comparison to pre-industrial levels, reef calcification rates are already compromised by the current level of atmospheric CO2. Under optimistic future emission scenarios (to 2050), the ability for reefs to continue to grow and recover from natural events such as cyclones is severely jeopardised,” said Dr Richards, who was not involved in the study.

“Under worst-case emission scenarios, reef dissolution appears inevitable and other unforeseen changes such as increases in microbial biomass are anticipated.”

Dr Richards said that the new study “demonstrates in an unprecedented way that the benefits of acting upon climate change are tangible and real for complex, dynamic and sensitive coral reef ecosystems.”

“If our goal as a global community is to protect, or at the very least, maintain the potential for coral reefs to grow, and ultimately, sustain the benefits they provide to humanity - there is no choice other than to curb CO2 emission levels,” she said.

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  1. Sean Lamb

    Science Denier

    While it is possible that coral ecosystems might have difficulties responding to sudden changes in environmental parameters, the idea that corals per se are restricted by sharp, narrow, upper boundaries relating to CO2 and temperature and simply "dissolve" is quickly refuted by looking at the late Jurassic period - CO2 1800 ppm.
    "The Late Jurassic was probably the all-time global maximum of Mesozoic coral diversity with at least 150 genera recorded in the European Tethys and 51 in the Panthalassa. "
    http://coral.aims.gov.au/info/evolution.jsp

    I should add that last year I was diving in Kavieng, New Ireland with ocean temperatures fully 2 degrees warmerthan the GBR and I can assure you coral was doing just fine.

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    1. Peter Campbell

      Scientist (researcherid B-7232-2008)

      In reply to Sean Lamb

      Good thing you are here to tell us you know better than the editors and reviewers for PNAS, one of the world's top science journals. Most scientists are happy if their work is rated highly enough to get into journals of this calibre only a few times in a career.
      Still, I guess you will be happy to have a parliamentary majority of 'science deniers' soon.

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    2. Craig Somerton

      IT Professional

      In reply to Peter Campbell

      And it is always the 'usual suspects' a collective of vocal intransigents who resolutely refuse to accept the vast wealth of data presented and the overwhelming scientific consensus of experts, because it doesn't fit their personal belief.

      I know it's hard, but we have to not feed the trolls because it just spurs them on even harder.

      The 'report' button under each post, should have an option to flag and remove their posts for "irrelevance" or "idiocy".

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    3. Whyn Carnie

      Retired Engineer

      In reply to Sean Lamb

      Now look what you have done, Sean. You have spoiled a good hypothesis with observations of fact. And stirred MWH to deny us the opportunity to join The Conversation on this.
      The article has stirred me to ponder how lowering ocean alkalinity can cause reduced Ca levels in corals and crustaceans and what happens to the CO2 otherwise sequestered. I can hardly wait to read the modellers' science on this.

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    4. Eric Ireland

      logged in via Facebook

      In reply to Sean Lamb

      Maybe those corals were adapted to higher CO2. Obviously the corals you saw in Kavieng, New Ireland were adapted to higher temperatures. Evidently the same cannot be said for the corals in this study.

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    5. Ove Hoegh-Guldberg

      Director, Global Change Institute at University of Queensland

      In reply to Sean Lamb

      Yes, all very good except that organisms adapt to the local conditions - given that CO2 has been below 400 ppm for tens of millions of years, one doesn't expect them to retained the ability to operate at 1800 ppm! That's just simply the principle of evolutionary adaptation. The other kicker in our current situation is that the current rate at which CO2 is rising is much much faster than most times in the biological history of the earth. Even during the spikes in CO2 in the past, the rate of change has been much much (10-1000 times) slower. If the environment moves that quickly, organisms are likely to be left behind given that evolution does take decades if not centuries to occur.

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    6. Ove Hoegh-Guldberg

      Director, Global Change Institute at University of Queensland

      In reply to Eric Ireland

      Which is correct. Corals that have been living in an area for more than a couple of hundred years tend to be physiologically tuned through adaptation to local conditions. Actually, taking corals from a situation where the temperature is a couple of degrees cooler and CO2 is around 400 ppm, and placing them under these ancient conditions of 1800 ppm (which is much higher than our experiment) and warmer temperatures not surprisingly yields corals which can't cope.

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    7. Chris Harper

      Engineer

      In reply to Ove Hoegh-Guldberg

      Professor Hoegh-Guldberg

      You said: "given that CO2 has been below 400 ppm for tens of millions of years, one doesn't expect them to retained the ability to operate at 1800 ppm!"

      Why not?

      What you stated here is an assumption, an hypothesis. Do you have data to back this up?

      Despite the CO2 impoverishment for the tens of millions of years you mention, plants have retained an ability to operate with higher CO2 levels. In fact, they thrive. In greenhouses horticulturists take advantage of…

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    8. Sean Lamb

      Science Denier

      In reply to Ove Hoegh-Guldberg

      Prof H-G, I was really replying to a presentation that suggested the destruction of coral was a physical-chemical inevitability rather than a biological-physiological phenomena.
      You may find the oceans possesses negative feedbacks or buffering capacity that will restrain ocean pH within a certain range.

      I couldn't find your paper on PNAS yesterday, it would be good practice if links were provided directly to the paper rather than the journal (just a general comment regarding these news and views articles).

      There seems a sort of trajectory in science. The first generation loudly proclaims GBR will disappear by 2030, the next generation sotto voce says something along the lines the ecosystem may shift in some directions.

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    9. Ove Hoegh-Guldberg

      Director, Global Change Institute at University of Queensland

      In reply to Chris Harper

      It is the outcome of scores of experiments which show when you expose corals to these high levels, they don't do so well. No need to be too surprised - it's called evolution by natural selection.

      Lots of papers to look at if you have time: start with this one that's just been published and which summarises lots of papers: Kroeker, K. J., R. L. Kordas, R. Crim, I. E. Hendriks, L. Ramajo, G. S. Singh, C. M. Duarte, and J.-P. Gattuso (2013), Impacts of ocean acidification on marine organisms: quantifying sensitivies and interaction with warming, Global Change Biol, 19, 1884-1896.

      As to your plant example - only proves my point in that the plants you refer to are adapted to high humidity is and temperatures - in this case human selection on top of natural selection has resulted in these plants/vegetables and fruits to invest in hothouses. As you'll find out, not all plants do well in such situations - which is a reflection of their evolutionary past.

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    10. Ove Hoegh-Guldberg

      Director, Global Change Institute at University of Queensland

      In reply to Sean Lamb

      As you'll see, the link to the journal now works. We made sure that the paper to be available to everyone. Unfortunately your last statement doesn't hold. When I first began to get information suggesting the reef was in trouble, 15 years ago, there was a lot of resistance ... but as people dug into the evidence and started to evaluate different studies that have been done, the situation has gone from feeling there might be a problem to the very serious concern that small excursions in atmospheric CO2 above 400 ppm will lead to the loss of the Great Barrier Reef. The coup de grace, of course, was the observation by the highly rigourous Australian Institute of Marine science which reported (also in PNAS) that the Great Barrier Reef had lost half of its coral ... De’ath, G., K. E. Fabricius, H. Sweatman, and M. Puotinen (2012), The 27-year decline of coral cover on the Great Barrier Reef and its causes, Proceedings of the National Academy of Sciences, 109(44), 17995-17999.

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    11. Doug Hutcheson

      Poet

      In reply to Whyn Carnie

      Whyn, try http://www.skepticalscience.com/Ocean-Acidification-Eating-Away-at-Life-in-the-Southern-Ocean.html and follow the links to the underlying peer-reviewed scientific publications.

      Key Points:

      Ocean acidification is occurring as a result of carbon dioxide emissions from industrial activity dissolving into the oceans, and involves a fundamental change in the chemistry of the global oceans.

      Perhaps the greatest challenge it presents to marine life that make their shells of calcium…

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    12. Whyn Carnie

      Retired Engineer

      In reply to Doug Hutcheson

      Doesn't do it for me, Doug, the key points have a few holes, peer review notwithstanding.
      The oceans are not "acidifying". In fact they are quite nicely buffered in the mild alkaline range. pH 7.0 is neutral and the oceans are above pH 8. A pH less than 7 would signify acidity and a fair bit less is required to make chalk dissolve. The CO2 in the atmosphere is in dynamic equilibrium with the CO2/CO3 in the oceans and has been since time immemorial. The little CO2 man may have added lately is miniscule…

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    13. Michael Wilbur-Ham (MWH)

      Writer (ex telecommunications engineer)

      In reply to Whyn Carnie

      Why bother to read The Conversation when people like Whyn Carnie have all the answers and can tell us why all the experts in the field are wrong.

      Whyn, you should set up your own website. Unfortunately your wisdom is wasted here because the readers here have a strong bias towards believing the academics. In fact the bias is so strong that I can't recall ever reading a comment from someone who has changed their mind due to a posting such as yours.

      If you set up your own website then you might attract some people who don't have a bias towards academics and rationality. So you might actually convince someone, and even better, we wouldn't have to read your non-science.

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    1. Mike Jubow

      forestry nurseryman

      In reply to Michael Wilbur-Ham (MWH)

      MWH, I agree with your sentiments wholeheartedly. All too often these pages are overtaken by the likes of of the deniers whose only aim is to disrupt the sensible flow of thoughts and practical suggestions. The tactic of cherry-picking an isolated part of a report and bogging the discussion down by micro-analyzing the small detail with the aim of deflecting thought and action from the main essence, in other words, they are a waste of space. If they can't read and understand the science, how do they…

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    2. Ove Hoegh-Guldberg

      Director, Global Change Institute at University of Queensland

      In reply to Michael Wilbur-Ham (MWH)

      One great thing about The Conversation is that you can have a rational exchange with the many good people that do come onto the site wanting to learn more and discuss. I agree, the deniers are annoying in their ideological nonsense, but the one great thing is that one can do is simply ignore them!

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    3. Michael Wilbur-Ham (MWH)

      Writer (ex telecommunications engineer)

      In reply to Chris O'Neill

      And vote Labor if you want to increase our1990 domestic emissions by 43% by 2020 (excluding land clearing) and want to export enough coal to provide 30% of the carbon needed to take the world to 2 degree warming.

      Labor might have a carbon price, but they are leading the western world in taking us to 4 degree or more warming.

      If you care do as I do, vote 1 Green.

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    4. Doug Hutcheson

      Poet

      In reply to Michael Wilbur-Ham (MWH)

      I have never voted Greens, but I have to agree with your assessment. It might be enough to push me over the line this time. I don't agree with all their policies, but I'm treating it as a one-issue election and the Greens are streets ahead on this. Sigh. Where is Malcolm Turnbull when he is needed?

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    5. Michael Wilbur-Ham (MWH)

      Writer (ex telecommunications engineer)

      In reply to Doug Hutcheson

      Malcolm Turnbull wanted the CPRS (which he helped water down).

      If this had passed then the current price on carbon would be only 1$ per tonne and this would not be able to be changed until 2010.

      So Malcolm was a champion of giving big business certainty, but he wanted to do this by locking in failure to adequately respond to climate change.

      And Doug, unless you are in a seat like Melbourne which the Greens might win, when you vote 1 Green you are just sending a message to both major parties…

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    6. Doug Hutcheson

      Poet

      In reply to Michael Wilbur-Ham (MWH)

      Michael, "there is a real risk that Abbott ... might gain control over the senate". Yes, the worst-case scenario is pretty grim. Unfortunately, I live in a rural, rabid right-wing electorate, so any vote for common sense will be swamped by the rusted-on National (LNP) supporters. Still, that's democracy at work and we have to cut our coat to suit the cloth. If I was serious about having my vote do some good, I would move to a marginal electorate, but that is a bridge too far for me.

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    7. Michael Wilbur-Ham (MWH)

      Writer (ex telecommunications engineer)

      In reply to Doug Hutcheson

      I'm in the same boat, but for me it is Kelly O'Dwyer who is certain to win.

      But at least our Senate vote counts as much as everyone elses in our state.

      Though Labor have been focussing on the margin seats, I think that after the election they will have to reconsider what they stand for. If the Greens vote falls significantly then Labor will probably remain focussed on winning the vote back from conservatives. If the Greens vote goes up significantly (which unfortunately I doubt) Labor might decide that it needs to become more progressive.

      So how we vote in the lower house might make a difference.

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    1. Ove Hoegh-Guldberg

      Director, Global Change Institute at University of Queensland

      In reply to Garry Baker

      There is quite a growing literature on the impacts of ocean acidification on non-coral like creatures. Organisms like pteropods in the Arctic, oysters and a whole range of other organisms show slower growth of their skeletons and shells when exposed to conditions like those we will see in the future if we don't stop pumping CO2 into the atmosphere. and beyond that of precipitating calcium carbonate, there's a developing literature on other impacts - such as gas exchange and fish (where changing pH can affect the exchange of gases) and in the neurological behaviour of fish - where changes in pH appear to affect the ability of fish to smell and navigate back to their home reefs.

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  2. Robert Edwin White

    Professor Emeritus

    I clicked on the only link PNAS in this report but could find nothing on coral reefs and decalcification in the Sept 3 issue. I did this to get at the original article rather than rely on the summary provided by the Conversation editor - could they possibly have given the wrong reference? How can one check on these claims and counter claims if we cannot see the original paper?

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    1. Sunanda Creagh

      Editor at The Conversation

      In reply to Robert Edwin White

      Hi Robert, You are right to want to see the original paper and normally we do include a link. The paper can be found here. http://www.pnas.org/content/early/2013/08/28/1302701110.short and I have updated the story to include a link. We couldn't include the link when this story was published yesterday because, at that time, although PNAS had lifted the press embargo, the link to the paper had not been activated. So the above link, had you clicked on it yesterday, would have led to an "error: page not found" message. Thankfully, PNAS has now activated the link. Thanks again for reading and taking an interest.

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  3. Mike Brisco

    Scientist at Flinders University of South Australia

    If my reading of the article is correct - acidified seawater also dissolves the "coral sand" ie the sediment of the reef. (right hand col; opposite fig 2 - sediment grains get smaller).

    What is to be done? Take photos and document it, so we can show future generations, what was there once. We value early colonial paintings, and settler diaries, for that reason, and they are all too few. Need to start making these records now...

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    1. Ove Hoegh-Guldberg

      Director, Global Change Institute at University of Queensland

      In reply to Mike Brisco

      The research team carefully weighed sand and other components within the system (before and after) and hence they were able to see the changes. What would be interesting is to try and document these in nature. Which I think will be difficult in the short term.

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  4. Jack McCadden

    Analyst

    This, and a growing number of other climate related observations seem to support a sense of urgency in tackling the CO2 problem. However, I'm constantly bemused with the most obvious (and only tangible) solution to excessive CO2 emissions - nuclear - is written off in Australia.

    Either the problem is urgent and we need an abrupt change of tack now. Or the problem is not so urgent and we can afford to wait 30 years or so for renewables to get to a point where base load coal can be replaced.

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    1. Michael Wilbur-Ham (MWH)

      Writer (ex telecommunications engineer)

      In reply to Jack McCadden

      Jack McCadden - The problem of climate change is so urgent that we can't wait the many years it would take to approve and then build nuclear.

      And note that urgent action is cutting our emissions by say 40% in ten years. This leaves 60% to be tackled later, giving renewables plenty of time to become more cost effective.

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    2. Ove Hoegh-Guldberg

      Director, Global Change Institute at University of Queensland

      In reply to Jack McCadden

      Unfortunately, the quicker we get off fossil fuels, or at least those fossil fuels that emit CO2, the better. given that we don't have good means for sequestering CO2 at scale from the burning of fossil fuels, we really have to move very quickly off them and move on to the many options as far as renewable energy. if we continue to emit CO2 at the rate that we currently emitting CO2 at (>2 ppm year-1) we will soar past 450 ppm in the atmosphere which is seen as too much of a coral reefs.

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    3. Steve Hindle

      logged in via email @bigpond.com

      In reply to Jack McCadden

      I agree there should be a lot more discussion on next generation nuclear energy, including the Thorium fuel cycle. Unfortunately there is so much ideological opposition to anything with the word "nuclear" in it that any discussion is quickly shouted down.
      Renewables fair poorly when it comes to producing base load power when the sun and wind are not available and thermal solar produces very little power at huge costs. Sadly without nuclear power the world will be building coal fire power stations for a long time to come.

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    4. Whyn Carnie

      Retired Engineer

      In reply to Steve Hindle

      The hidden problem in continuing to use coal to produce most of our electricity is that it will reduce the coal stocks that are needed to produce coke to produce iron. If nothing else, the global warming/climate change fears have led us to make inroads into more efficient use of all fuels. A huge benefit that nuclear power brings is the potential to reduce the tonnes of coal required currently to produce iron and steel. The electrical requirements of the steelmaking process can never be met from renewable sources. That alone ought to be sufficient to sway the anti-nuclear power lobby to look again. There have been major advances in nuclear reactor technology. The quantity of truly 'waste' radioactive material by products has been reduced to easily managed quantities.

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    5. Steve Hindle

      logged in via email @bigpond.com

      In reply to Whyn Carnie

      I see the fervent dismissal of the nuclear energy option by many (but not all) conservationists as a growing tragedy. I am all for renewable energy as it can economically be used, but it looks very much like coal will be used in large quantities into the foreseeable.
      I don't think there is any need to worry about running out of coal, either thermal or metallurgical coal, as there are truly vast quantities of the stuff still in the ground. The worry is continuing to burn so much of it. Nuclear can do what thermal solar can't, produce power 24/7 at realistic costs.

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    6. Michael Wilbur-Ham (MWH)

      Writer (ex telecommunications engineer)

      In reply to Steve Hindle

      I see nuclear as a major distraction from debating what needs to be done now.

      And our energy future needs the power we need when we need it. This does not mean that we need base load generation (always on but hard to turn up or turn down).

      Nuclear might be a part of some countries solutions, but it is far too difficult politically and isn't' needed for Australia - so it won't be a part of our solution.

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  5. Paul Prociv

    ex medical academic; botanical engineer

    This phenomenon has intrigued me for a long time, and I have no doubt about the finding's conclusions, even though the full article is unavailable, so the precise test conditions are not clear (e.g. what levels of ambient CO2 were used?). However, I continue to have just one niggling question, the answer to which has been elusive, despite my contacting a range of authorities for clarity, so far with no response.
    Sure, ocean pH is falling, due to rising dissolved CO2 reacting with water to form…

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    1. Ove Hoegh-Guldberg

      Director, Global Change Institute at University of Queensland

      In reply to Paul Prociv

      a. The test conditions are outlined in full detail in the article and the online material.

      If you have any further questions regarding the conditions, just give me a holler.

      b. The problem is that carbonate is also in equilibrium with bicarbonate which doesn't precipitate, obviously, as calcium carbonate. Yes see, as you add CO2 to seawater - it combines with water to create a dilute acid - that then dissociates into a proton and bicarbonate ion. The proton then reacts with a further…

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    2. ian cheong

      logged in via email @acm.org

      In reply to Ove Hoegh-Guldberg

      it is rather vague from the abstract if the study is a real world controlled experiment or a computer model. full paper not opening ??paywalled.

      can you post a pre-pub somewhere so we can look???

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    3. ian cheong

      logged in via email @acm.org

      In reply to Paul Prociv

      paul, we have a friend who is a competent research biologist. she says her research shows corals growing better in higher CO2 which disagrees with other published papers. she explains the methodological flaws of others. i recall talking to her about problems for her publishing such work - usually gets rejected by apparent editorial bias.

      cheers.

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    4. Michael Wilbur-Ham (MWH)

      Writer (ex telecommunications engineer)

      In reply to ian cheong

      ian cheong,

      I have a friend who says your friend doesn't know what she is talking about. And another friend says that my first friend is correct, and one of her friends has confirmed that there is no editorial bias.

      So clearly you don't need to worry because my friends have sorted things out :)

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    5. ian cheong

      logged in via email @acm.org

      In reply to Ove Hoegh-Guldberg

      ok article downloading now. i could not find a description of a control mesocosm running in parallel.

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    6. ian cheong

      logged in via email @acm.org

      In reply to ian cheong

      to clarify - was there verification that the control behaved similarly to the real reef?

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  6. ian cheong

    logged in via email @acm.org

    science moves forward on the basis of rational skepticism. there is no room for name calling in science. research conducted in an environment pro-warming is likely to be confounded by bias. time and more research will reveal scientific truth. there is no such thing as consensus in experiments. well performed experiments provde robst repeatable results. not so well done experiments may be overturned by scientifc inquiry.

    anyone professing to know the outcome of an experiment is not a scientst.

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  7. Comment removed by moderator.

  8. Gerard Dean

    Managing Director

    I will get the usual brickbats for bringing discretionary JetA1 fuel burning into this discussion, however it is bang on topic because the article calls for reducing green house gas emissions.

    Surely waiting for governments to act on greenhouse emissions is folly - why don't the people who really care just stop flying. It is a simple, cost effective way of reducing our greenhouse emissions and will be good for Australia's domestic tourist industry.

    The problem area is the ethical justification for academics who tell me to reduce my use of fossil fuels, yet continue to burn them themselves.

    One day this will all be over.

    Gerard Dean

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    1. Michael Wilbur-Ham (MWH)

      Writer (ex telecommunications engineer)

      In reply to Gerard Dean

      Gerald - You have been making this point for I think several years now.

      What I can't understand is how you can just keep saying the same thing as if your comment has not been answered. It has been, not once, not twice, but literally hundreds of times.

      Not only are you wasting everyones time, this comment has become incredibly boring.

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  9. Chris Reynolds

    Education Consultant

    The deeply depressing prospect of this election that the carbon emissions pricing scheme may be abolished is deeply deeply worrying, We have ample evidence that man made carbon emissions are accelerating global warming and yet the Abbott Opposition has subscribed to voodoo economic policies involving massive amounts of unworkable carbon sequestration and green armies none as yet identified and doing no one knows what. It is called direct action. Ic all it unscientific busy work a fig leaf to cover…

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  10. Doug Hutcheson

    Poet

    "reef calcification rates are already compromised by the current level of atmospheric CO₂". So, the much-touted limitation of warming to 2°C does not protect us from devastating changes in the ecosystem we occupy. In spite of all the rhetoric, bad things are going to happen - are already happening - and we have lost the first battle against global warming. Dissolution of the Great Barrier Reef is a real possibility, if this article is accurate. That'll do Queensland tourism no favours.

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