Discover 2012

One of the main reasons I haven’t posted for a while is that all my spare “communication” time and energy (and more!) have gone into organising exhibits for a public engagement event this week: “Discover 2012”, part of National Science and Engineering Week.

These things always take much more work than you initially think…. Virtually all our exhibits are new this year. We’ve got three tables of the 22 at the event, and have gone a bit overboard in the number of exhibits to create redundancy: inevitably some break and go wrong on the day, or aren’t so successful with the public once you test them.

My friend and colleague Jenny Griggs has helped me with all the organising. About nine of us have designed the exhibits, with technical and practical support from our department (Geographical Sciences), and 37 of us – mostly post-doctoral researchers and PhD students – from Geography, Earth Sciences, Engineering and Maths to demonstrate the exhibits.

Anyway, I thought I’d show you what I’ve been up to and advertise it here. Needless to say, if you are in or near Bristol please do come along. I’m on shift tomorrow morning and also around at the end of Saturday.

Discover 2012

For National Science and Engineering Week

This Thursday to Saturday, 8th-10th March 2012, from 9am-6pm, The Galleries (Broadmead), Bristol, UK

Press release:

Ocean acidification

Carbon dioxide from fossil fuels is not only causing climate change but also making the oceans more acidic.

Race against your friends to make your water more acidic by blowing through a straw!

Try making sea shells bend and fizz with vinegar.

See how burning candles makes the surface of our “ocean” more acidic.

Climate quiz

Our well-loved interactive quiz about the earth, geography, weather and climate. Free sticker for taking part, “gold” sticker if you get to the end!

Ice is cool

Find out how ice comes in different kinds and different places in the world…even South America!

How much of our iceberg has melted? Has it changed the “sea level” in our tank?

Antarctic ice flow

Did you know ice can flow like a liquid? Our “slime” is like liquid ice. Be a scientist for a moment (with your own lab coat!) and race the liquid ice to the edge of Antarctica.

Antarctic explorers

What did Scott and his team wear in Antarctica? What do scientists wear there now?

See photographs and a children’s book about Scott’s expedition, and how different modern Antarctic expedition clothes are (on a mannequin!).

Greenland E-tracers

Scientists at Bristol throw detectors that look like Christmas baubles (“E-Tracers”) down holes in Greenland to measure water underneath the ice. Sometimes they get lost…

Throw your own E-tracer down a hole in our “glacier” – which one will come out first? Or will it ever come out…?

“Film trailer” and documentaries

Electronic tracers – a spoof film trailer and 3 film clips about E-Tracers.

Life on the Ice – a documentary about a group of scientists (including University of Bristol glaciologists!) spending three weeks in the world’s most northerly town.


Do come along!



  1. Barry Woods

    This is JUNK science for public consumption..

    “Carbon dioxide from fossil fuels is not only causing climate change but also making the oceans more acidic.

    Race against your friends to make your water more acidic by blowing through a straw!

    Try making sea shells bend and fizz with vinegar.

    See how burning candles makes the surface of our “ocean” more acidic.

    an insult to the public, the ocean is not acid, nor could it ever be.
    the phrase seems to carefully become the ‘convention’ to make it sound more scary, tapping into previous ‘acid rain’ stories.

    You do not alkanalise an acid – you neutralise it. and vice versus.
    An annoyed educated member of the public, with a BSc Applied Chemistry.

    • Tamsin Edwards

      Hi Barry. Thought you’d say that. Our water in the exhibit all starts at neutral, so we are acidifying. And in the “cribsheet” for the demonstrators it says making the oceans “less basic/alkaline”.

      And I’ve stressed at both training sessions that we should be careful not to scare children, make them think the oceans are acid, and so on. It’s an exhibit learning about pH, about household products with different pH levels, about how CO2 can dissolve in water and lowers pH. Come to Bristol to check up on us if you like 🙂

      • John Russell

        Best to ignore Barry and his, ‘AGW is not a problem’, agenda, Tamsin.

        I have a Bristol Uni graduate son who still lives and works there and I’ll suggest he visits. I’ve been trying to encourage him and his 2 brothers to take an active interest in climate science (it’s their future after all) but they all seem to think that writing code, cycling and playing softball is more interesting.

        • Tamsin Edwards

          Some of climate science is writing code 🙂 And lots of climate scientists (and geographers, geologists, glaciologists) are keen on cycling (and hiking, climbing,…).

      • Barry Woods

        I do hope you advise the PUBLIC..

        that the oceans are alkaline, that pH can vary on a daily basis orders of magnitude more than the projection for this century, on a weekly, daily, monthly basis in coastal regions..

        May I ask why are you dipping sea shell in an acid… what is the point, what are you trying to convey..

        As it has absolutely nothing to do with whatever can happen in the ocean, whilst it may be fun for the public. What is being conveyed – alarm?

        Why not have a few other oceans, and dip the shells in at pH8.0, pH 7.9, pH 7.8 pH 7.7 and watch nothing happen..

      • Barry Woods

        Tamsin learning about PH is great…

        But in the above we have in the Ocean Acidification section, dipping sea shells in vinegar, and a neutral ocean making it acidic.. and having I imagine an ‘alarming effect’ on sea shells..

        and burning a ‘candle’ (fossil fuel) to make the (neutral unrepresenatitie) ocean more acidic,

        not very subtle is it?

        What ‘message’ will the public take away, what ‘message’ do you (Bristol) want the public to take away. What have they actually learned about ocean pH and the real environment (very little)

        so it sounds rather more than learning about pH and household objects. very disappointing

        Vinegar is acidic in nature as it is a solution of acetic acid. The exact pH of vinegar depends upon how much acid is present, but most commercial distilled white vinegars contain 5-10% acetic acid and have a pH roughly around 2.40 – 3.40.

        pH oceans (varies 7.8 -8.1)

        • Lauren Gregoire

          Hi Barry,
          The candle experiment is our best experiment, it demonstrates the exchange of CO2 between the air and the sea and that it’s the surface of the ocean that will change pH first. As for dissolving shells in vinegar, it’s a basis to explain that calcium carbonate in the shells can dissolve in “undersaturated” conditions. The high latitude ocean may become “undersaturated” with respect to calcium carbonate in the next century because of fossil fuel emissions.
          You’re right, it’s important to make clear that oceans aren’t and will not become acidic. We’ll be really careful about that.

  2. Weather Badger

    Good luck with all this. It’s great to get the public thinking!
    Barry Woods sounds like he needs “a free sticker” to perk him up. A few weeks ago I spoke to a class of 5 year olds about the weather and got them holding hands to make a snowflake. I’m sure some kids weren’t forming the correct 6 sided lattice shape, but at grass roots level surely it’s more about inspiring/sparking imagination/desire. I’m sure you will do just that. They can then go and do a BSc in Applied Chemistry.
    Cheers and keep up the good work.

    • Tamsin Edwards

      Thanks WB. As you say the main idea is to show science – and scientists! – as interesting, not to send them away with their heads full of information.

      • Barry Woods

        There is simplification for an aufience.

        1000 primary school children expected.

        And misrepresenting science to convey a ‘message’

        Kids Dipping sea shells in an ocean the kids have made acidic. Is not subtle, and imho beneath contempt.

        Do they go away knowing that the sea is alkaline, could never be an acid and varies naturally, far more than co2 ‘acudification’ projections…..?

  3. Liz Stephens

    Well done for getting this all organised Tamsin, I know it has been a tough month for you (not helped by me!)

    Yes, it is simplification for the audience. It’s about getting kids interested in science, giving them an idea of what scientists do and that we don’t all have grey beards. I can see your concern but I know those presenting the exhibits will not be convincing the audience that the sea is going to become an acid, rather that scientists at Bristol are carrying out studies that look at what might happen to the ocean with increases to CO2 in the atmosphere.

    Do you think that the take home message being: if the sea absorbs CO2 then it will lower the pH and that things that live in the sea might be affected by it, is misrepresenting the science?

    As for your acidification / neutralisation concerns, I think it is an issue of semantics. To me, neutralisation sounds like something out of a Bond film where everything is going to be wiped out, so acidification is much less dramatic! I’m also pretty sure that when I was at school I was taught that when the pH is lowered then acidification has taken place, even if the final solution is still not an acid. I appreciate that at higher levels of study that ‘neutralise’ might be used as the strict scientific term, but I think it is better to use the same (simplified) language that is used in schools.

    • Barry Woods

      There are enough studies around showing increasing co2 increases coral and marine life growth and is beneficial.. but hey, stick to ‘acidification’ and negative experiments, shells dissolving in acid…

      When they get a bit older. They will find the oceans are alkaline, PH varies naturally quite a lot, especially coastal/tidal. Actually taken accurate PH , even with identical calibrated instrumentation side by side, is complicated, the data is sparse, poorly collated, and compared to the small amount projected C02 changes in 50-100 yrs, that this was just a latest public scare..

      And they will perhaps trust science and their teachers a little bit less.

      Why I dislike this sort of thing. My child came home from school a little while ago, saying polar bears are during because of humans, with pictures of co2 and polar bears, and she ran around turning the lights off.. she was 5 at the time.. and in tears.

      Why not just save bullets(lomborg)

      Real world, rich Chinese businessmen, shoot adult male polar bears, about 500 a year, $50,000 s time, because the inuit are exploiting their licences.. numbers polar bears go up… bcos adult males are shot, who normally, when encounter a female and cubs attack the cubs..

      So humans are artificially affecting the population.. upwards. Which may then cause a population crash. Too many bears. Simple science vs complex natural environment

      • Barry Woods

        Using the same’simplified’ language used in schools and in the media is the problem….

        • Liz Stephens

          I don’t think that is true. It’s about finding the balance between ensuring that the scientific integrity is not lost and that the message can be understood by whoever it is intended for. There are many cases where the science requires simplifying to remove unnecessary jargon or over-detailed explanations that can’t be understood by the lay-user, the vast majority of people in this country do not have any scientific qualifications above GCSE and this surely should be reflected in the communication.

          I’m also no expert on acidification (sorry neutralisation :p ), so can you point to the studies that show that increasing absorbed CO2 in the ocean is beneficial to corals and marine life? Not trying to be picky, just like to be able to look at the papers if I haven’t heard of them!

      • Irony Tag

        Barry, this is an area I haven’t spent much time looking at. I know that coral and marine life can get along just fine within a range of ph levels. However, I have not seen a study that says if the oceans absorb more CO2 that it increases coral and marine life growth. Can you point me to a reputable study or studies that report that?

        I’m not arguing, we probably agree on most things climate, but that’s something I haven’t seen before.

  4. Nick

    Hey Barry, think you need to seriously edit the Wikipedia article on ocean acidification, as it seems to suggest there might be some minor problems there!

    To be honest, I expected that people of the fingers-in-ears variety would be using ocean uptake of CO2 as a very welcome negative feedback for taking it out of the atmosphere?

    Anyway, good work on the public engagement Tamsin, I hope you enthuse some kids to study science for themselves so they can verify these things for themselves someday.

    • Nick

      Sorry Tamsin, that was a little argumentative; it’s just, you know, sometimes… feel free to moderate the hell out of me!

    • Barry Woods

      So rather than discuss any of my substantive points you just choose an insult.. ocean PH is a very complex issue, simplifying it into acidification scares, and that attitude, just alienates people.

  5. Peter Major

    I have been trying to find out it anyone is using satellites to monitor heat radiated from the planet. It seems like a basic piece of scientific research but I cannot find anything. Do you know or be able to point me in the right direction.

  6. James P

    “making the oceans more acidic”

    Doesn’t that imply they are acidic in the first place?

    I’m with Barry on this – we (and you) know that the ocean is alkaline, but most people who have heard the green message about CO2 ‘acidifying’ it assume that it will soon be something like vinegar! Even David Attenborough conveys this sort of message, implying that corals will all soon disappear like Alka-Selzer. If the warmists were honest, they would say ‘less alkaline’, but they don’t.

    • Sceptical Wombat

      It is ridiculous to talk about the oceans becoming more acidic when they are an will remain alkaline, just as it is ridiculous to say that Texas is further south than Virginia when both are in the Northern Hemisphere. We should say that the oceans are becoming less alkaline and that Texas is less north than Virginia.

    • Sceptical Wombat

      Having said that I’m not sure that I would use vinegar to demonstrate the effect. It does leave you somewhat open to ridicule and the message you are trying to convey gets lost.

      • Tamsin Edwards

        We had an exhibit using ‘goo’ (the slime you make from glue and borax) as ‘liquid ice’ flowing in Antarctica. I told them this was because we didn’t have time (in 3-5 mins) to see ice flow but it showed the general idea and pointed to a photo of a Dry Valleys (Antarctic) mountain to show them ice flowing. I see the vinegar similarly, as showing a principle quickly, though I do appreciate that there is more scope for confusing one pH level for another than confusing ice with slime 🙂 But the demonstrators were clear in saying that the oceans are not acidic like vinegar and that the extent of vulnerability is uncertain.

  7. Nullius in Verba

    Here’s an entertaining question to add on for any more advanced students (or their parents), who perhaps know a little GCSE chemistry.

    When carbon dioxide dissolves in water it forms carbonic acid H2CO3. (H2O + CO2 = H2CO3.) Seashells are made from Calcium Carbonate CaCO3.

    If you drop a seashell into fizzy carbonated water (which is acidic), can you write down the equation of the reaction that takes place?
    H2CO3 + CaCO3 = ? + ?

    I admit, it’s cruel! But I find the educational value in demonstrating that facts they previously accepted as ‘obvious’ may be more complicated than they believed to outweigh the potential confusion about the sea’s potential de-alkalinisation. (Is that a word?)

    Of course, the oceans are already acidic enough to dissolve seashells – it takes biological ion pumps in mollusc cells to change the pH inside enough for shell to form. Whether shellfish will be affected by pH changes is therefore less a chemistry question than a biology one. Can they possibly adapt? Well, we only have to ask what the atmospheric CO2 level was back in the geological era when molluscs first evolved.

    • Dave H

      > Can they possibly adapt? Well, we only have to ask what the atmospheric CO2 level was back in the geological era when molluscs first evolved.

      Rate of change would seem to be an important factor too, no?

    • Steve Bloom

      “Well, we only have to ask what the atmospheric CO2 level was back in the geological era when molluscs first evolved.”

      There’s something rather important that NiV doesn’t know about (hint: if you Increase atmospheric CO2 a lot and keep it there, what happens to ocean pH over the long-term? How does the rate of increase in CO2 affect the change in pH?). Oh wait, that was two things, and now a third: What happened to ocean life during the entirely natural sharp “dealkalinization” excursions of the past? A fourth thing: Why would we not expect the even sharper excursion in the present to have similar or worse consequences should it continue its present trajectory?

      Never mind, I’ll come in again. 🙂

      It doesn’t seem to have been linked already, so in addition to the material offered by Fred Moolten and John Russell here are some fresh results:

      Ocean Acidification Rate May Be Unprecedented, Study Says

      The world’s oceans may be turning acidic faster today from human carbon emissions than they did during four major extinctions in the last 300 million years, when natural pulses of carbon sent global temperatures soaring, says a new study in Science. The study is the first of its kind to survey the geologic record for evidence of ocean acidification over this vast time period.

      “What we’re doing today really stands out,” said lead author Bärbel Hönisch, a paleoceanographer at Columbia University’s Lamont-Doherty Earth Observatory. “We know that life during past ocean acidification events was not wiped out — new species evolved to replace those that died off. But if industrial carbon emissions continue at the current pace, we may lose organisms we care about — coral reefs, oysters, salmon.”

      The oceans act like a sponge to draw down excess carbon dioxide from the air; the gas reacts with seawater to form carbonic acid, which over time is neutralized by fossil carbonate shells on the seafloor. But if CO2 goes into the oceans too quickly, it can deplete the carbonate ions that corals, mollusks and some plankton need for reef and shell-building.

      That is what is happening now. In a review of hundreds of paleoceanographic studies, a team of researchers from five countries found evidence for only one period in the last 300 million years when the oceans changed even remotely as fast as today: the Paleocene-Eocene Thermal Maximum, or PETM, some 56 million years ago. In the early 1990s, scientists extracting sediments from the seafloor off Antarctica found a layer of mud from this period wedged between thick deposits of white plankton fossils. In a span of about 5,000 years, they estimated, a mysterious surge of carbon doubled atmospheric concentrations, pushed average global temperatures up by about6 degrees C, and dramatically changed the ecological landscape.

      The result: carbonate plankton shells littering the seafloor dissolved, leaving the brown layer of mud. As many as half of all species of benthic foraminifers, a group of single-celled organisms that live at the ocean bottom, went extinct, suggesting that organisms higher in the food chain may have also disappeared, said study co-author Ellen Thomas, a paleoceanographer at Yale University who was on that pivotal Antarctic cruise. “It’s really unusual that you lose more than 5 to 10 percent of species over less than 20,000 years,” she said. “It’s usually on the order of a few percent over a million years.” During this time, scientists estimate, ocean pH — a measure of acidity–may have fallen as much as 0.45 units. (As pH falls, acidity rises.)

      In the last hundred years, atmospheric CO2 has risen about 30 percent, to 393 parts per million, and ocean pH has fallen by 0.1 unit, to 8.1–an acidification rate at least 10 times faster than 56 million years ago, says Hönisch. The Intergovernmental Panel on Climate Change predicts that pH may fall another 0.3 units by the end of the century,to 7.8, raising the possibility that we may soon see ocean changes similar to those observed during the PETM.

      More catastrophic events have shaken earth before, but perhaps not as quickly. The study finds two other times of potential ocean acidification: the extinctions triggered by massive volcanism at the end of the Permian and Triassic eras, about 252 million and 201 million years ago respectively. But the authors caution that the timing and chemical changes of these events is less certain. Because most ocean sediments older than 180 million years have been recycled back into the deep earth, scientists have fewer records to work with.

      During the end of the Permian, about 252 million years ago, massive volcanic eruptions in present-day Russia led to a rise in atmospheric carbon, and the extinction of 96 percent of marine life. Scientists have found evidence for ocean dead zones and the survival of organisms able to withstand carbonate-poor seawater and high blood-carbon levels, but so far they have been unable to reconstruct changes in ocean pH or carbonate.

      At the end of the Triassic, about 201 million years ago, a second burst of mass volcanism doubled atmospheric carbon. Coral reefs collapsed and many sea creatures vanished. Noting that tropical species fared the worst, some scientists question if global warming rather than ocean acidification was the main killer at this time.
      The effects of ocean acidification today are overshadowed for now by other problems, ranging from sewage pollution and hotter summer temperatures that threaten corals with disease and bleaching. However, scientists trying to isolate the effects of acidic water in the lab have shown that lower pH levels can harm a range of marine life, from reef and shell-building organisms to the tiny snails favored by salmon. In a recent study, scientists from Stony Brook University found that the larvae of bay scallops and hard clams grow best at pre-industrial pH levels, while their shells corrode at the levels projected for 2100. Off the U.S. Pacific Northwest, the death of oyster larvae has recently been linked to the upwelling of acidic water there.

      In parts of the ocean acidified by underwater volcanoes venting carbon dioxide, scientists have seen alarming signs of what the oceans could be like by 2100. In a 2011 study of coral reefs off Papua New Guinea, scientists writing in the journal Nature Climate Change found that when pH dropped to 7.8, reef diversity declined by as much as 40 percent. Other studies have found that clownfish larvae raised in the lab lose their ability to sniff out predators and find their way home when pH drops below 7.8.

      “It’s not a problem that can be quickly reversed,” said Christopher Langdon, a biological oceanographer at the University of Miami who co-authored the study on Papua New Guinea reefs. “Once a species goes extinct it’s gone forever. We’re playing a very dangerous game.”

      It may take decades before ocean acidification’s effect on marine life shows itself. Until then, the past is a good way to foresee the future, says Richard Feely, an oceanographer at the National Oceanic and Atmospheric Administration who was not involved in the study. “These studies give you a sense of the timing involved in past ocean acidification events — they did not happen quickly,” he said. “The decisions we make over the next few decades could have significant implications on a geologic timescale.”

      Read it and weep.

  8. Fred Moolten

    Hi Tamsin – It’s a pleasure to visit your blog, and to read the interesting (and sometimes very informative) commentary, usually done in a civil manner.

    I wish you much luck with Discover 2012. The educational process is very important. Regarding ocean acidification, I have the impression that it is not only the public but also the scientific community that is much less aware of the phenomenon than might be warranted, given its potential importance. As part of educating both scientists and science teachers on this subject, I’ve written an article on Ocean Acidification – “The Other CO2 Problem”, that summarizes what I interpret to be the major current conclusions of experts in this area (I’m not an ocean acidification expert, but I have some familiarity with the subject). If knowing about this resource is of any use to you, I hope you’ll take a look.

  9. Swiss Bob

    Have to say I agree with Barry.

    I AM interested in the science, not advocacy or ‘propaganda’ and I’m afraid everything I’ve read about ocean ‘acidification’ is just that, propaganda given the actual facts.

    PS I did enjoy the previous article because I learnt something interesting, in this article I learnt something depressing.

  10. John Costigane

    Well said, Bob.

    Some fun can made of this off-topic topic from Tamsin. My choice for a third scare-mongering phrase is – hyper biodiversity-ification. The increase in plant growth, for example, poses a deadly threat to man’s leisure activity. Grass will soon grow so quickly that mowing the lawn will be required every 2 weeks, instead of 3, in the spring/summer/autumn.

  11. Bloke down the pub

    Hi Tamsin, welcome to the trenches.
    I recall that some of the things I was taught in geography in my early teens would now make an expert cringe. What was made to sound plausible then sounds rediculous now. Be careful with predictions you make now as you will hopefully still be around when mother nature provides the answers. Good luck with enlightening the little darlings.

    • Tamsin Edwards

      Hi Bloke down the pub,

      Revising predictions and theory in the light of new evidence is what science is all about – we’re not going to sit on our hands refusing to give an answer until we know everything, because that will never happen…

  12. orkneylad

    Sounds like ‘discover 2012’ might be a touch to apocalyptic for my tastes!

    Barry’s points are well founded I feel, young children have very imaginative minds & if you tell them the oceans are becoming ‘acidic’ and combine it with shell-melting, you’re well on the way to creating nightmares visions.

  13. Fred Moolten

    It seems to me that there are a number of misconceptions in some of the above comments that are worth addressing, involving both content and semantics.

    Regarding content: If you visit the references in my article on ocean acidification, with particular attention to the meta-analysis in Kroeker et al, but also the others, it’s clear that ocean acidification has varied biological effects, but that overall, they are substantially negative. The most vulnerable organisms are the calcifiers, but metabolic effects can adversely affect survival and reproduction of non-calcifying species as well. Only a relatively small number of species appear to benefit, and even fewer at the bottom of the food web. Some of these are photosynthesizers, but even here, possible growth benefits of higher CO2 are meager, because there is sufficient carbon in the ocean to make changes in atmospheric CO2 a relatively minor factor.

    It’s also important to recognize the difference between laboratory experiments under protected conditions, and changes in the ocean itself, where stresses from predation, wind, and other forces impose stronger demands on the calcification process than in the laboratory, so that organisms that tolerate lesser carbonate saturation in lab experiments do poorly under field conditions.

    On the semantic side: The use of the prefix “acid…” for pH reductions at values greater than pH 7 has a long and well established history. The best known example is in medicine, where normal blood pH is 7.4. Patients with a lower pH are classified as suffering from “acidosis”. A pH of 7.3 is considered mild acidosis, whereas a pH of 7.1 would be considered severe, life-threatening acidosis.

    More generally, it’s a well-established semantic principle that words have no intrinsic meaning, but derive their definition from how they are used. Lexicographers record definitions based on common usage by reputable individuals in a discipline where the words are used, and “ocean acidification” fits that pattern, just as does “acidosis” for a blood pH below 7.

    The use of the word “alkaline” here can also cause problems. It would certainly be correct to state that ocean pH is becoming less basic, but it would be an ambiguous statement to say it’s becoming less alkaline. In ocean chemistry (and also for individuals with swimming pools and aquaria), total alkalinity has a specific meaning – it refers to the total concentration of ions capable of buffering added hydrogen ions. In the oceans, there are a number of such species, but of particular importance are the concentrations of bicarbonate, twice the carbonate concentration (because it can bind two hydrogen ions), and OH-, all minus the H+ concentration. Paradoxically, adding CO2 to the oceans slightly increases its total alkalinity even as it reduces its pH. This happens because the reaction of carbonic acid with solid calcium carbonate in sediments and calcified organisms causes some of that solid to be released as bicarbonate ion in solution, adding to the alkalinity. (In the absence of any solid CaCO3, added CO2 would leave total alkalinity unaltered).

    Finally, individuals studying ocean acidification have been using the term among themselves with little attention focused on public reactions until the last few years, and I know of none who dreamed it up as a scare tactic. Nevertheless, if one conceives a mental picture of “acid causing things to dissolve”, this picture does in fact have relevance to the observation that increasing the ocean’s hydrogen ion concentration facilitates the dissolution of the CaCO3 exoskeletons of marine organisms, even when the pH is above neutral.

    • James P

      “it would be an ambiguous statement to say it’s becoming less alkaline”
      How about ‘more neutral’?

      As for “I know of none who dreamed it up as a scare tactic” I take it you have nothing to do with Greenpeace or WWF or the BBC? They’ve been dining out on it for some time…


      • Fred Moolten

        Hi James – The ocean could become more neutral from either direction, so the term wouldn’t be too informative. I have the sense that the people who have been working on this for many years (long before it got caught up in public partisanship) wouldn’t have objected to some term other than “ocean acidification”, but that term is so entrenched now in the scientific literature (and relevant searches) that it would be impossible to change it. There is some virtue in “acidification”, in that it is the increase in hydrogen ion concentration that impairs the ability of calcifying marine organisms to maintain the integrity of their calcium carbonate exoskeletons, and which can adversely affect the internal metabolism of other organisms.

        The best we can do, in my opinion, is to describe as accurately as possible what is actually happening, both chemically and biologically, and hope that intelligent audiences will make sound judgments.

        • James P

          Fred – I can’t argue with much of that, but you call ocean acidification ‘the other CO2 problem’. Could you expand on what you think the first one is?

          • Fred Moolten

            James – When “CO2” and “problem” are mentioned in the same sentence, most people assume the topic is global warming. How much of a problem that is will obviously be debated, but that’s what people have in mind when they read the word “problem”.

            If your question was designed to see if I would defend the notion that global warming is a problem, I’d like to put that discussion off for another time.

          • James P

            Thanks, Fred. I agree that the popular perception is that CO2-based warming is the ‘main’ problem, but I have doubts about the linkage. There seems to be an increasing argument of the mechanism (e.g. ‘back-radiation’) and my simplistic view is that it is hard to ascribe a major effect to such a minor component (1/2500) of the atmosphere.
            A discussion for another day, perhaps. Tamsin? 🙂

          • Alexander Harvey


            One might ask the degrees to which it is the amount of IR active gas (GHG) in the atmosphere or the concentration that matters. One might alter the concentration by varying the amount of IR inactive gas, e.g. Nitrogen and hence wonder whether lowering the concentration of CO2 by adding more N2 would lessen the effect of the CO2. Could one dillute the IR effect of CO2 by diluting its concentration?

            In the IR band where CO2 is measured to be active, N2 is similarly inactive. If such IR radiation passes by N2 molecules as if they were not there what would change if they were not there?

            Certainly the mass of the atmosphere would change and hence the surface pressure. Would increasing the mass or the pressure act to lessen the IR effect of the CO2?

            It is standard practice to quote the CO2 content of the atmosphere in terms of ppmv but it could be given as an absolute amount by weight or molecular count, the amount per cubic metre at varying locations, or the amount in a column above each square metre of the surface. One can ask which of these is important in terms of the IR effect of CO2.

            In terms of calculating the IR effect of CO2 in terms of radiative transfer it is the amount not the concentration that seems to matter, although the pressure does have some direct effect. The pressure has a broadening effect on the spectral lines which if anything increases the magnitude of the IR effect.

            I doubt that concentration be the most appropriate measure when considering IR effects.


          • Fred Moolten

            Alex – I agree that in a given total atmospheric volume, CO2 IR absorption is a property of true concentration (e.g., molar) rather than of its ppmv representation, although the latter is a reasonable approximation of what happens to actual concentration when CO2 is emitted into the atmosphere. Increasing atmospheric N2 might “dilute” CO2 to the extent that the same number of molecules were distributed into a taller column, but the radiative effect of this change isn’t necessarily easy to predict. In any case, though, I expect the net effect would be a significant increase in absorption because of increased pressure broadening, particularly at low altitudes (high pressures). A smaller climatic effect in the opposite direction would be an increase in atmospheric albedo from Rayleigh scattering.

            I’m sure there would be other effects as well, but these are the main ones that occur to me.

          • Tamsin Edwards

            As has been said, CO2 forcing climate is off-topic people… Bit busy to check every comment as it comes through so please try not to take advantage 🙂

            I am finding the ocean chemistry conversations interesting – I don’t know so much about it or the ‘dissenting’ views – so I’ve left these even though strictly they are tangential to the original post.

          • James P

            Tamsin – do you have a view on CO2 induced warming? I know your hands are a bit full at the moment, but there seems to be plenty of room for debate on the subject. I’ll try to leave it alone until then, though!

          • Tamsin Edwards

            I try to keep things on topic: either the site topic (how to test the usefulness of earth system models) or post topic (eg communicating the science).

    • Fred Moolten

      In my paragraph above on semantics and intrinsic meaning, I intended to refer to a pH above 7, not below it in referring to “acidosis” in medical terminology.

  14. Steve Bloom

    Gee, Fred, it’s almost as if the argument about the terminology is a smokescreen to avoid grappling with the substance of the science. 🙂

    Much thanks for the article and further elucidation.

    Or, er, should I say deopaqueification? 🙂

  15. Nullius in Verba

    I’m glad you found it deopaqueifying, because I struggled with it a bit. Perhaps you could help?

    First, I was surprised to discover that the majority of oceanic organisms had been tested, for us to be able to make statements about how most of them respond. If you did a meta-study of all the papers on how global warming affected species, wouldn’t we find in most of them the answer was ‘adversely’? Isn’t there a potential selection effect at work here?

    Any species adapts to the normal range of circumstances it finds itself in (or finds circumstances it is adapted to). Pushing them outside that range, they usually do less well until they can adapt. The questions are whether this is possible and if so how quickly can they do it? ‘First generation’ adaptation is only a part of the answer.

    I was curious about the list of factors that make the ocean different from the aquarium, and put more stress on organisms. The first of these was predation. If an organism gets eaten, how does its response to CO2 change? And is this not a good thing for the predator?

    The second was “wind”.

    If that’s not the common usage of the word, perhaps that’s not the least opaque term that might be used for it?
    And I didn’t find it obvious that it would be a stressor, in moderation. It encourages circulation and a constant flow of nutrients. Aquaria generally have to be oxygenated artificially because of its lack.

    And the third was “other forces”. But I remain unenlightened.

    The semantics is a minor point. I thought it was clear that the issue wasn’t whether the term was understandable and technically accurate, but the emotional effect.

    The discussion on alkalinity is good. It starts to touch on some of the complications I had alluded to. But I was a bit surprised to see right in the middle of it: “the reaction of carbonic acid with solid calcium carbonate”. I’m sure I had already mentioned this one?
    CO2 + H2O + CaCO3 = H2CO3 + CaCO3 = ? + ? + ?

    It sounds like simple acid-salt chemistry, until you think about it for a moment.

    Sometimes people drop the Calcium and write it as:
    CO2 + H2O = H2CO3 = HCO3(-) + H(+) = CO3(2-) + 2H(+)
    You increase the concentrations on the left hand side, so which way does the equilibrium move? Is it obvious?

    This sort of thing is common in teaching science to children. You take something that is complicated, and give them instead a simple and vaguely plausible explanation they can understand. For getting kids enthusiastic about science it’s great. But it has a major drawback if you don’t go back and fill in the gaps, in that kids grow up thinking its simple, and when somebody else comes along claiming it is more complicated they will conclude somebody has been deceiving them. Either the ‘idiot’ who can’t even understand the basic physics/chemistry they learnt at school, or their teachers. Either way it’s damaging. So I’m wary of explanations selling science as simple, with no caveats.

    Grappling with the substance of the science takes time. It will take people a while to catch up with this new approach.

    • Fred Moolten

      NIV – I don’t think we have space here for a comprehensive answer to all your questions, but I think most are addressed fairly well in the article I mentioned and even more in the references. Here, for what it’s worth:

      1. To get a good perspective on how ocean organisms respond by testing only a fraction, you need an adequate sample, not a testing of most or all organisms. Once sample size is adequate, its fraction of the total population becomes largely irrelevant. The various studies listed in Kroeker et al report a variety of outcomes, some beneficial, but more adverse. Bias is always possible, but my experience with the literature on this suggests that there has been a concerted effort in some quarters to selectively report beneficial effects, whereas the more comprehensive studies have been more careful to report all outcomes. I have seen no evidence that groups who have wanted to belittle the importance of ocean acidification have inadvertently overlooked examples of its benefits, but readers should visit the references I’ve listed to judge for themselves.

      2. I’m not sure exactly what point you wanted to make regarding adaptation. The various references provide details of paleoclimatologic data on species declines and extinctions associated with high CO2, low pH climates, including the selective decline of those organisms that one would expect most likely to be vulnerable. Adaptation in those particular cases has apparently been inadequate. Obviously, other species have undergone some adaptive changes. The main concern with current acidification is its rapidity – with changes occurring over decades to a century or so rather than millennia. These are the circumstances that in general are associated with threatened extinctions as well as declines in species that will ultimately survive. This is what threatens the food web. To be accurate, though, it’s fair to say that current damage to the food web from humans has probably come mostly from other activities such as overfishing.

      3. Important stresses in the wild include damage to coral reefs from predators that require extensive repair processes to restore integrity. Diseases are also a factor. Mechanical factors include wind/wave-driven erosion and tidal forces. Human influences, including pollution, can also play a role in damaging these structures. There is no problem with having predators benefit from their predation if the balance isn’t distorted by the acidification process.

      4. I agree that the semantics are unimportant. At the same time, the term “acidification” accurately represents the chemical species most responsible for adverse effects – hydrogen ions.

      5. The equilibrium constants for the various reactions favor the formation of bicarbonate from carbonate at the various concentrations found in the oceans. The net effect of exposing CaCO3 to CO2 and H20 is to generate Ca ions and bicarbonate ions as described in my article. I didn’t write it as H2CO3 ionizing to yield H+, which then reacts with carbonate ions, because I could not find literature that dissected the details of the reaction mechanism as opposed to the net result, but the latter appears to be well established.

      6. Since I agree with you that it’s desirable not to sacrifice accuracy for simplicity, I avoided doing that, but rather tried to represent the evidence as accurately as possible. As far as I know, I haven’t stated anything that would turn out to be different if analyzed in detail, even though I haven’t described every possible detail.

  16. Steve Bloom

    Too much selection effect can equal mass extinction. The PT extinction, for example, was a wonderful opportunity for scleractinian corals to evolve, their predecessors having left a big empty niche when they couldn’t adapt quickly enough. So it took many millions of years for the new corals to appear, but who’s counting.

  17. Nullius in Verba

    Thanks for the reply. I agree there isn’t space here for a comprehensive debate on whether acidification is a problem. I don’t know enough about the question to decide, so my position at the moment would be “I don’t know”. My main point was separate from that, though, and is that whether it is or it isn’t, the science is complicated. Selling a simple story, with caveats to let readers know there are complications, is ok if you know for certain that the more complicated story comes to essentially the same conclusion. But in this case I don’t know for certain, and I strongly suspect that science doesn’t either. We’re dealing with pan-species biochemistry and ecology here. The science is relatively undeveloped.

    In such circumstances I would expect scientists to be saying “We don’t know” and emphasising the complications, rather than selling simple stories confidently expressing alarm. That may just be my perspective, of course.

    1. There are several selection effects that might occur. One obviously is that people are looking for evidence to support (or oppose) the movement on reducing CO2 emissions. A disparity in the number of people doing each leads to a bias in the outcomes. Another is that researchers pick species to investigate if there is prior reason to think they might be more strongly affected (e.g. that they have shells that might dissolve). A third is that researchers want to report a result. “We added CO2 and nothing happened” doesn’t look so good; it doesn’t persuade the funders that the research is useful. So they will keep looking, pushing the pH levels or changing the conditions until they get a reaction. A fourth is the ‘Millikan effect’ – When Millikan measured the charge on the electron, he got it a bit wrong. If you follow the history of subsequent measurements by other experimenters, they start out near Millikan’s value, and drift slowly to the correct value. It is believed that this is because experimenters will search more assiduously for errors if they get an unexpected result than if they get an expected one. They ‘knew’ the right answer before they started, so if they got the wrong answer, they searched for errors and corrected them until they got close, and then they stopped.

    I agree a sample can be sufficient – but the other essential condition of sampling is that the sample is taken uniformly and independently. The species studied and the results reported are not necessarily either.

    It’s not just a question of dishonesty or deliberate bias. Science invests in controls and randomised trials and double blind studies because it has discovered that there are unconscious biases to deal with too.

    2. My point about adaptation was that we need to ask the right question. As you say, it isn’t the level but the rate of change that gives cause for concern. So the question is can the ecology adapt faster than it is changing? I don’t know the answer to that one. I suspect the answer would be that it can – the history of pesticide and antibiotic resistance illustrates how fast life can adapt, and the pH of the oceans is not really constant anyway. Rapid, short-term variations are common. But I wouldn’t want to make any confident assertions.

    3. Oh, I see what you mean now. A coral reef isn’t a single organism. Each individual coral polyp prospers or dies independently. Damage to one part of the reef doesn’t hurt the rest – it’s an opportunity for expansion.

    Disease and pollution I’d agree with. Although you can get disease in lab specimens too.

    4. Agreed.

    5. Sorry. I had assumed that by asking the question, the issue would become obvious. I think I need to explain some more.

    When a strong acid is mixed with a salt of a weak one, the stronger acid displaces the weaker one. For example:
    2HCl + CaCO3 = CaCl2 + H2CO3 = CaCl2 + H2O + CO2
    This is where we get the idea that putting acid on limestone releases carbon dioxide. Chloride switches with carbonate, and then the carbonic acid produced breaks down.

    However, if we try the same thing with carbonic acid, we find ourselves substituting a carbonate for a carbonate. The calcium carbonate is a salt of carbonic acid itself, so carbonic acid cannot displace it. (Or rather, the end result of the displacement looks identical to the starting conditions.)

    Adding CO2 to pure water to form carbonic acid increases the number of carbonate ions. Increasing the concentrations on the left hand side pushes the equilibrium to the right. Calcium carbonate is less likely to dissolve in pure carbonic acid than it is in pure water.

    What’s really going on here is a more difficult and counter-intuitive effect to do with ‘alkalinity’. Because the water is salty, and has cations from many other species, adding CO2 moves the first couple of equilibria to the right, but it moves the rightmost one to the left. It reduces the carbonate concentration in favour of bicarbonate. This is not obvious.

    You see, it’s not the conclusion that I think is wrong, but the explanation. Saying “the reaction of carbonic acid with solid calcium carbonate” is only half the story, and makes people think they know what’s going on when they don’t.

    The reason I think this is important is the the same thing happened with the greenhouse effect. The physical effect is real, but the explanation given to the general public was wrong. In fact, there were a whole sequence of wrong explanations – that it is like a greenhouse, that shortwave radiation can get in but longwave cannot get out because the glass/atmosphere is opaque to IR, that it is like a blanket, that heat is blocked from escaping and trapped, that IR is absorbed by GHGs and re-radiated back to the surface, warming it. They’re all wrong, and climate scientists know it.

    They argue that you have to keep it simple for the public, especially if you want to persuade them. People are far more convinced if they think they understand. They argue that so long as the correct explanation is in the textbooks and scientific literature, it’s ok to bamboozle ordinary people with bogus explanations backed up by scientific authority.

    The actual result of doing this has been to sow confusion and fuel scepticism. People with enough knowledge to realise something is wrong (but not enough to figure out exactly what) run headlong into people who blindly trust the experts. The believers insist the simplistic explanation is right and anything else is anti-science, the sceptics tie themselves in knots trying to figure out their own answers, and can’t understand how the believers can have such confidence in a theory they don’t understand and can’t explain.

    I’m fed up of knocking down “backradiation violates thermodynamics” arguments. I don’t look forward to having to do the same in future for ocean acidification.

    • Nullius in Verba

      Minor correction – just realised I said cations when I should have said anions.

    • Fred Moolten

      NIV – The meta-analyses and other surveys of biological effects of ocean acidification don’t conclude that most organisms are affected – we don’t know that – but that when effects are observed, they are most often negative. This gets to a question of scientific honesty/integrity. It’s reasonable for a scientist not to publish data showing no effect, but it would be dishonest for scientists observing both negative and positive effects to report just the former and withhold the latter. I think the overall negative biological effects of ocean acidification, despite exceptions, are now well substantiated, but I agree we can always use additional evidence.

      Regarding the chemistry, the addition of CO2 drives carbonate ions in the net direction of bicarbonate specifically because of the particular concentrations that exist in the ocean/atmosphere system, including the availability of solid CaCO3 as a carbonate source. Obviously, if you add CO2 to pure water, you increase both bicarbonate and carbonate. In the oceans, that is not what happens, based on the equilibrium constants and the supply of solid CaCO3.

      • Fred Moolten

        It wasn’t my intention to leave the impression that the dissolution of CaCO3 from added CO2 could easily be derived from back of the envelope calculations, but only that the reaction proceeded as I described under ocean/atmosphere conditions. The actual calculations are somewhat complex.

  18. JSmith

    Quibbling over words because they sound scary, sounds to me like the way some people say ‘the big C’. rather than ‘cancer’. Or ‘passed away’, rather than ‘died’.
    Or even, more relatedly, ‘climate change’ rather than ‘global warming’ – less frightening, according to Frank Luntz, because it sounds more benign and nothing much to worry about.
    Yes, the words may be scary but, as long as they are relating facts (which this presentation appears to be) they must be said.

    • Tamsin Edwards

      That Republican document about changing from “global warming” to “climate change” is interesting, but of course the reason scientists use the phrase “climate change” is that it is more general – it includes changes in the biosphere, in cryosphere, the hydrological cycle and so on, and also regional rather than global change.

      Having said that, when my Dad died (two years ago next Tuesday) I found “passed away” and “lost” infuriating: as if wrapping the words in cotton wool was going to make it all better. I understand it was well-meant, but at the time it felt like the instinct to do it came from protecting their own sensibilities rather than my feelings.

      I pronounce myself off-topic!

    • Steve Bloom

      It’s been noted for a while that something like “anthropogenic climate disruption” is much more to the point, but it hasn’t caught on.

    • Steve Bloom

      That’s an interesting view of history, JSmith, considering that both the IP*CC* and and the UNFC*CC* both substantially predate any such discussion.

      • JSmith

        Of course, Steve Bloom – but those who naively try to claim that ‘GW’ was surreptitiously changed to ‘CC’ (for whatever reasons they can imagine, but definitely part of that all-encompassing conspiracy !) can be majorly confused when you tell them that, actually, a certain political viewpoint (usually the same one held by those making the ‘surreptitious’ claims) prefers ‘CC’, and has done since at least 2003.
        To me, ‘GW’ and ‘CC’ are interchangeable.

  19. Marilyn

    Hi Tamsin

    Hope it goes really well this weekend. Will be interested in hearing which experiments were the most popular/most successful. I do sort of worry about kids taking away the message that oceans are acidic but it honestly depends on how the info is presented to them and I’m sure you will all be being really careful about this – so shouldn’t be a problem at all.

    Climate change in various forms now pops up in schools in year 7, year 8 and year 10 physics so it’s always good to hear about different ways of getting various messages across and keeping it up to date too. 🙂

    • Tamsin Edwards

      Thanks Marilyn. We had a giant pH scale and pointed out where the ocean is on it. And also the first question on our FAQ sheet was “Can we make the oceans acidic? No. [followed by explanation]”. But very happy to hear further advice if you have some.

      • Tamsin Edwards

        I should say we showed what the average pH is on the scale. We also had a map of the spatial pattern, and a time series showing large variability around the trend.

        Once I’ve done a write up of what worked and what equipment we used I can send it to you 🙂 Thanks for commenting.

  20. Gras Albert

    Tamsin, in general your presentation sounds fun, but I’m I agreement with Woods, and as usual in very great disagreement with Moolten…

    In the Cambrian period, when atmospheric CO2 was 20 times higher than the 20th century (Cambrian, 7000ppm) the ocean teamed with life, in fact almost every metazoan phylum with hard parts, and many that lack hard parts, made its first appearance in the Cambrian., the first corals appeared in the Cambrian but only became widespread in the ocean during the Ordovician, when atmospheric CO2 had reduced to just 15 times 20th century (4000ppm) and have thrived ever since. Almost every paper that Moolten references on any subject shows the confirmation bias associated with the annual $bn grant funding for research which supports the dangerous CO2 increase meme, even when, as in this case, it is patently absurd.

    I find the phrase ‘Ocean Acidification’ risible and it’s use anywhere, base!

    • Fred Moolten

      Albert – I won’t take the space here to respond in great detail, because the referenced sources in my article address the paleoclimatologic evidence in detail, but your comment does give me the opportunity to make a few points.

      First, most organisms from that ancient era later became extinct. Second, the specific correlation between high CO2/low pH on one hand and decline or even regional extinction of many species is well established, with particular emphasis on calcifying organisms at the bottom of the food web. In most eras, it has been possible for organisms to survive if they were evolutionarily adapted to the ambient conditions over thousands or millions of years, but then to decline when the conditions changed.

      Perhaps an even more important point is this, however. The most serious danger from ocean acidification is the reduction in carbonate saturation that threatens the integrity of the CaCO3 exoskeletons of most calcifying organisms. However, high CO2 and low pH will not greatly reduce carbonate saturation if it occurs gradually over many thousands or even millions of years. The reason is that the carbonate is gradually replaced through buffering in the ocean by carbonate sediments whose own mass is restored by inflow of carbonate (mainly in bicarbonate form) from the weathering of silicate and carbonate terrestrial rocks. It is when the acidification occurs rapidly – over centuries or less rather than many thousands of years or more – that the restoration process can’t keep up and carbonate saturation declines to damaging levels.

      One of the problems with discussions of this topic, in my experience, is that evidence is often presented selectively with the goal of supporting a bias. This can happen of course in any direction, but it includes selective citation of articles designed to present ocean acidification as a minimal or non-existent threat. The other extreme is evidence cited to claim that major damage has already occurred. I think that the references I’ve cited will give readers a more objective view, indicating that while there is some evidence for adverse effects that have already occurred, most of the danger resides in the possibility that CO2 will continue to rise and the acidification will continue to progress to the point of more widespread harm.

    • Steve Bloom

      Albert, Fred corrected you on the long-term buffering point, but I wanted to single out your statement that “the first corals appeared in the Cambrian but only became widespread in the ocean during the Ordovician, when atmospheric CO2 had reduced to just 15 times 20th century (4000ppm) and have thrived ever since.” As I had mentioned above, a major difficulty with this sanguine view of things is that these corals subsequently went extinct, coincident with the acid spike and other environmental effects associated with the PT mass extinction event. Modern corals had to re-evolve subsequently.

      If you could, I’d like you to pause for a moment and consider how you can make such strong statements without knowing these basics.

      • Nullius in Verba

        I hadn’t wanted to say anything, since I haven’t researched the topic thoroughly enough to be sure – but I didn’t think the point about long-term buffering was correct, and picking out the acid spike as the causal factor in the extinction event seems a case of correlation/causation – it needs to be justified more carefully. The corals may have died for some other reason – the other chemistry changes resulting from the same cause.

        Fred says “First, most organisms from that ancient era later became extinct.” But the point is that they evolved and survived in that ancient era – what happened millions of years later is irrelevant to that. Over the vast majority of the history of life, CO2 levels have been far higher than they are now. And shellfish and other marine organisms have survived just fine in it. The point is that this demonstrates that it is possible; that it is just a matter of biology. (For that matter, freshwater and land molluscs make the same point.) It doesn’t prove that their modern descendants can always survive the same conditions, but it’s not unreasonable to suppose they might. We don’t know.
        For that matter, we don’t know that there haven’t been previous short-term variations of the modern-day magnitude. If it didn’t leave a distinctive trace (and if nothing much happened as a result, why should it?) we could easily not know about it. It is a classic error in paleontology to presume that what we can see is all there was.

        Another point is this idea that evolution can only happen over thousands or millions of years. There’s no reason to think that at all – it depends on the details. And I’ve no idea what “Modern corals had to re-evolve subsequently” means. If you mean that corals have continued to evolve subsequently and are no longer quite the same as their ancestors, then that’s obvious, and would happen anyway. If you mean that every form of coral died out and corals re-evolved from scratch from some other sort of organisms, I don’t think it’s true. Modern corals are the descendents of the few corals that survived.

        Nor did I understand what was meant by “the carbonate is gradually replaced through buffering in the ocean by carbonate sediments”. The only sense I can make out of it is that if the lysocline rises, some seabed carbonate deposits will fall below it and be dissolved, but this is surely a very small effect? Does it mean that with a higher lysocline, the suspended ‘sediments’ will dissolve? Besides not being the usual definition of ‘sediment’, surely under these pH conditions that will increase bicarbonate, not carbonate?

        The reference to the carbonate-silicate cycle I did understand, but I don’t think it would stabilise carbonate levels in the oceans in that way. Acid rain weathers silicate rocks turning them to carbonate, which eventually becomes sediment under shallow seas, which is subducted and turned back to silicate, releasing CO2 from volcanos. Presumably your idea is that high CO2 makes rain more acid, causes more rapid weathering which feeds more carbonate into the oceans. But this is just an indirect way of saying the high level of CO2 dissolves in water, producing carbonate, the silicate rocks performing the same role on land that alkalinity does in the ocean. Just replace volcanos with power stations.

        The basic problem with this idea is that weathering depends on more than just the acidity of rain. It also depends on the land mass exposed, how much of it is sillicate, how much is exposed rather than buried under vegetation, and the general level of vulcanism. It’s a feedback with other things swinging on the control lever; it’s not going to lead to stability. Witness the recent rise of the Himalayas, and the resulting precipitate drop in CO2 to some of the lowest values ever.

        As I said, I don’t know enough about the subject to tell for sure. But it looks to me like scientists are offering speculation and hypotheses to try to explain events and inconsistencies they don’t fully understand – not totally implausible, but far from settled science – and people are downplaying the uncertainties and presenting their speculations as authoritative to make it seem more solidly alarming than it actually is.
        Worryingly, we have advocates and activists using the “peer-reviewed literature” as an argument from authority, and we’re already seeing anyone who questions it or asks about apparent anomalies and inconsistencies being portrayed as biased or ignorant of the ‘basics’. There’s a danger this will go the same way as the climate debate, if it hasn’t already.

        It’s a complicated subject. We don’t know a lot about it. It will take a while to get educated. And honest questions/doubts and clear answers from both side are to be welcomed.

        I appreciate Fred trawling through the literature and summarising what the scientists are saying. I’ll express my doubts about it, but we do need to listen carefully to the arguments to see if they make sense. Even when they’re expressed with more confidence than we think is justified.

        • Fred Moolten

          NIV – Thanks for your latest comment. I probably wasn’t as clear as I should be regarding evolution and extinctions. Organisms can start discernibly to evolve within hundreds of years or less under conditions that disfavor their current genetics (minutes for some microbial species), but that means that their numbers and reproductive fitness will decline during the evolutionary process. It doesn’t mean that they will be fine while evolving, even if they don’t become extinct. We do know of mass extinctions, including coral species, during some previous high CO2/low pH intervals, and the change in chemistry may well have contributed (among other factors), but we can also assume that changing conditions caused changes in species abundance even for those that survived.

          We also know that even today, a minority of species appear to do well under high CO2/low pH conditions, and so the past existence of species that thrived under those conditions tells us little about how the majority of today’s calcifiers and other organisms would do. The evidence tells us that most would suffer a decline, even if thousands of years from now, they will be replaced by better adapted species. Compared with a decline in numbers, extinction of marine species is probably not our most immediate concern, although it is the most dramatic expression of impaired growth and reproduction.

          Weathering serves as a source to restore ocean carbonate concentrations depleted by the CO2-mediated carbonate to bicarbonate conversion process, and thereby helps to maintain carbonate levels sufficient for saturation even if the pH has declined. This helps calcifying organisms and also helps maintain the level of non-biological CaCO3 that aids in ocean buffering capacity. Some of this is discussed in the Honisch et al Science paper referenced in the comment at the end of my article.

          • Fred Moolten

            NIV – In rereading your comment, I think I still failed to make clear everything I wanted to say. In particular, CO2 added to ocean water reduces carbonate concentrations, but weathering of silicate rocks by rainwater containing CO2 yields a runoff (Mg++ ions and HCO3- ions as one example) that ends up increasing ocean carbonate (as well as bicarbonate). Here, the buffering occurs on land, and augments rather than depletes ocean carbonate stores.

          • Nullius in Verba

            Don’t worry about the scientific details. I would tend to agree that it is very difficult to compactly explain this area of science in a couple of blog comments. I was only picking at it to show the difficulties with quick explanations, because I thought Steve was being too quick to draw conclusions.

            I really wanted to make two points: one on science education and the other on the way the debate is going.

            Science education is about giving students models of the world. They necessarily start off with simple models, and work their way up. The thing missing that seems important to me here is that you have to know the model’s limits – its domain of validity – to safely use it. I have no problem with giving kids a simple model like ‘acid eats limestone’ to start with so long as they know there’s more to it, and it’s actually quite complicated. Giving them a few unresolved mysteries or leaders into more advanced stuff is a good way of doing that. The problem with the picture of science kids grow up with is that it is too neat and clean and certain. It leaves them unprepared for the real world.

            The other is that the same problem I note in science education for kids also applies to the public debate with the adults playing. Complicated and uncertain new science is being presented using simplified explanations that give the impression that it’s actually simple, and therefore fairly certain. And this has implications beyond the science. I only picked apart your explanation to show how we miss things when we read them, and what seems obvious and plausible at first glance can actually be somewhat tricky. It’s not to say you don’t have answers for my questions, it’s to point out that there are legitimate questions. No matter how far we go, there always will be.

            All models of reality are wrong, some are useful, but to use them safely you have to know where the boundary between ‘wrong but useful’ and simply ‘wrong’ is.

            So I’m concerned when the simple pictures are presented as simply ‘true’ because ‘teacher says so’, (or ‘scientists say so’,) without an understanding that these nice neat stories have their limits. And I’m disturbed when differing viewpoints, scepticism and doubt, and reasonable questions/objections (even if they’re wrong) are discouraged on the grounds of their not having understood the ‘basics’.

            Science has to constantly re-examine its foundations; its logical support stays fresh and live only because the arguments are constantly being revisited and re-argued. Dogma is a sign of politics, not science. The use of the words ‘it’s obvious’ is a ringing bell; a stone in need of turning over to see what is underneath.

            So apologies to Tamsin for diverting so far off-topic. I didn’t really have a problem with your explanation – I have a different view on it, but that’s ok – I only wanted to make the point that simple explanations (models of the world) have limitations that we have to look out for. It was an illustration that asking questions is reasonable.

  21. KnockJohn

    As it happens, a friend of mine has just released a paper on lowering of pH and its effect on copepods. – it does make for very interesting reading. The effects measured after doing the experimentation were not as Dan had expected.

    Secondly – on the use of the work acidification, yes it is a misnomer but it is the word in general parlance. I often wonder whether an increase in pH would lead to similarly alarmist stories of CAUSTIC seas.

  22. John Costigane

    Being off-topic is no crime, though contention exists even here. In the rush to move science on, I have forgotten the value of this website which can be as successful as Judith Currry’s Climate Etc..

    Discover 2012 is a worthwhile effort since science education has suffered recently with young people doing Arts subjects instead. As ever, learn from the experience. Future events can then be even better.

  23. NZ Robin

    I have an idea. Rather than say more acidic, say less caustic. And show some of the effects of highly caustic substances like KOH or NaOH.

  24. James P

    Just a passing thought – what happens to the pH if the ocean warms and releases CO2?

    • Fred Moolten

      James – Warming the ocean reduces CO2 solubility. Under current atmospheric conditions, the ocean is a CO2 “sink”, in that a substantial fraction of CO2 added to the atmosphere is absorbed into the ocean – probably about 25%. This is true because the effect of the increase in atmospheric partial pressure of CO2 significantly outweighs the reduced solubility. If, however, the ocean were to warm for some other reason, in the absence of a preceding change in atmospheric CO2, the result would be a net transfer of CO2 out of the ocean into the atmosphere, leading to an increased CO2 concentration as a response to warming rather than a cause. This is a phenomenon that has occurred during transitions from glacial intervals to interglacials such as the current Holocene, where the initiating event was a change in the Earth’s geometric relationship to the sun – so-called “orbital forcing”, although multiple factors beyond simply reduced solubility played a role. The increased CO2 then exerted its own warming effects, as a positive feedback on the initial warming.

      That didn’t completely answer your question about pH, because even at a fixed ocean CO2 concentration, pH will exhibit some temperature dependence, and I’m not sure how that would change as a function of current ocean chemistry, but I expect the main changes in pH are those that reflect changes in the concentrations of dissolved CO2.

  25. Pharos

    Oh my! I am as disturbed by this post as Barry Woods was. Perhaps even more so, as it targets primary school children. With due respect to Fred and Steve for their views, sincerely held I am sure, the suggestion than an anthropogenic CO2 driven increase within the extraordinary and dangerously low ambient CO2 atmospheric Quaternary concentrations we find ourselves in, is in any way analogous to the mass extinction crisis at the Permo-Triassic Boundary, as indeed the blame for it laid at the door of the big pariah CO2, is pure Gleikian extremism.

    Nullius in Verba said:
    ‘I don’t know enough about the subject to tell for sure. But it looks to me like scientists are offering speculation and hypotheses to try to explain events and inconsistencies they don’t fully understand – not totally implausible, but far from settled science – and people are downplaying the uncertainties and presenting their speculations as authoritative to make it seem more solidly alarming than it actually is.
    Worryingly, we have advocates and activists using the “peer-reviewed literature” as an argument from authority, and we’re already seeing anyone who questions it or asks about apparent anomalies and inconsistencies being portrayed as biased or ignorant of the ‘basics’. There’s a danger this will go the same way as the climate debate, if it hasn’t already.’

    I agree.

    But I have to say, that surely we can spare scientifically defenceless primary school children from this post normal alarmism?

    Why not give them experiments illustrating conventional meteorological phenomena, like formation of dew and frost, evaporation, condensation, or even tell them that CO2 is actually a vital link in the plant growth life cycle.

    And tell them about the classic geology around Bristol, and suggest an excursion such as to the Avon Gorge, an SSSI heritage site, where Vaughan established the Lower Carboniferous stratigraphic succession on the sequence of corals and brachiopods. Explaining that right there conditions were near tropical and under a shallow sea. And tell them how the gorge was cut through those uplifted and tilted limestone strata at the height of the glacial advance, when conditions were permafrost, not so long ago? And so much more wondrous stuff like that.

    Save the ‘Carbon dioxide from fossil fuels is not only causing climate change but also making the oceans more acidic’ stuff for later, please.

    • Fred Moolten

      Pharos – First, thanks your generous willingness to believe that my views on our current “dangerously low CO2” concentrations are “sincerely held”.

      My lame attempt at being snide aside, I do think you and Nullius in Verba make some important points. First, it would be wrong to suggest that current changes in ocean pH are placing us in a circumstance analogous to the PT extinction. If my article in CAMEL and my comments here suggested that, I clearly was inadequate in stressing that what I referred to was the direction of change and its potential future implications rather than the current magnitude, and that there is to date, little evidence that the reduction in pH from a pre-industrial value slightly exceeding 8.2 to the current 8.1 (about a 30% increase in hydrogen ion concentration) has done much harm, although there are isolated examples where this may be starting to happen. I also think, though, that it’s legitimate to be concerned about eventual harms that fall short of massive species extinctions. Human civilization has much dependence on the bounty of the sea, and even modest declines far short of mass extinctions can have serious consequences. The danger is somewhat exacerbated by the fact that some of the very vulnerable organisms are central to the food web, so that their decline will affect species that are not themselves greatly affected by ocean acidication.

      The second point I believe you two make is that it’s important not to overinterpret evidence. I certainly agree, but I think that if you read the references I listed at the end of my article, you’ll find that the authors have been scrupulous in this regard. In particular, they make clear that there is no time in the paleoclimatologic record when everything was the same as today except for atmospheric CO2, and so many factors entered into the biological changes that transpired. The potential harm from ocean acidification doesn’t rest convincingly on any single piece of evidence, but on a combination of separate pieces derived from paleoclimatologic data, recent field observations, laboratory experiments, and basic chemistry. As more evidence accumulates, our perceptions are likely to be modified, although I suspect they won’t be dramatically reversed. In any case, I hope interested readers will visit the references to draw their own conclusions about the evidence.

      Finally, I hope Tamsin will weigh in regarding the science exhibits involving acidification. I know that it’s difficult to reproduce climate change exactly in an exhibit setting. To accurately illustrate CO2 greenhouse effects in a literal fashion, you would have to build an air-containing column 15 kilometers high, and to literally illustrate dramatic effects on the calcified exoskeletons of marine organisms from a small decrement in ocean pH, you might have to wait months or years. The challenge would be to devise exhibits that illustrate the principle accurately even if the conditions must be adapted to work in the setting of an exhibit. I have the impression that the exhibit Tamsin describes attempts to do this with demonstrations using low pH environments to illustrate the role of hydrogen ions, but accompanied by explanations that the pH of the oceans is on the basic side.

      • Pharos

        Thanks for the courteous reply. I would not disagree that increasing atmospheric CO2 will result in slight reduction of pH in cold boreal temporate waters, but in all likelihood lost within the range of natural variation. We must remember that our extant fauna and flora has a remarkably robust phylogenetic evolutionary heritage that has endured and survived the entire gamut of the trials and tribulations of natural ecological variability and stress to date, including what I would still geologically categorise as the current ‘critically’ low (for photosynthesis and growth) ambient Quaternary atmospheric CO2 concentration. What I despise, is articles such as this

        which at least is frank enough to reveal the purpose of the alarmism thus

        ‘Katherine Richardson, a marine biologist at the University of Copenhagen, who organised this week’s event, has described it as “a deliberate attempt to influence policy”. She said many scientists were concerned that politicians have not grasped the seriousness of the situation, despite increasingly gloomy predictions.’

        • Steve Bloom

          So shocking that the people most familar with the problem think they should have some involvement in getting solutions implemented. I mean, think of it, if this sort of thing catches it could be taken to extremes; for example out our legislative bodies might become packed with lawyers. Oh wait…

          Sorry, Pharos, the way the world is organized subject-matter experts generally do get an outsize voice in policy (relative to non-experts). But I’ll bet you have no problem with that principle in areas where you don’t object to the policies.

          • Pharos

            Thanks Steve. But it is prudent to be sure of a problem before agitating to get a solution implemented. Following up on your upthread pasted summary from the news article, and interested to read it having been trained as a micropalaeontologist myself, I find the original Lamont Docherty paper by Bärbel Hönisch et al here


            In this paper, towards the end, the authors wisely include caveats that perhaps have been inadvertently understated in press releases:-

            ‘What Are the Perspectives for Using the Geological Record to Project Global Change?- Only rapid or pulsed CO2 release events can provide direct future-relevant information. Assessment of such events critically depends on independent geochemical quantification of the associated changes in the carbonate system, specifically seawater-pH and CaCO3 saturation. Geochemical proxy estimates are not yet available for the Cretaceous and beyond and need to be obtained to verify whether ocean acidification did indeed happen. This is challenging, because in addition to the potential for increasing post-depositional alteration and reduced stratigraphic exposure, uncertainty over the chemical and isotopic composition of seawater increases and limits our interpretation of these proxies (63, 64). Future studies will have to improve and expand geochemical estimates and their uncertainties of surface and deep-ocean carbonate chemistry associated with carbonate dissolution and ecological changes. This includes finding new archives to study the secular evolution of seawater chemistry but also the laboratory study of living proxy carriers under conditions mimicking past seawater chemistry. An unfortunate aspect of the geological record, however, is the lack of deep-sea carbonates in the Early Jurassic and beyond, which further reduces our ability to reconstruct the carbonate chemistry of those older events…etc.

      • Tamsin Edwards

        Yes, I’ve said this elsewhere – we are trying to demonstrate principles quickly. The main part of the exhibit is blowing through a straw into indicator liquid to see it lower the pH. They like to twice their friends.

        We focus on climate, glaciology and ocean acidification because those are the research topics of the people that designed the exhibits. Geology would be the domain of the Earth Sciences department (I believe they do a school thing called Rocks and Soils). Weather also isn’t a research focus in itself.

  26. Jack Hughes

    Sorry Tamsin I don’t like this.

    If you wanted to get children excited about science you could do hundreds of experiments with magnets, with gyroscopes, with lenses and mirrors etc etc.

    You could avoid anything controversial or political and stick to the fun and wonder of science.

    • Tamsin Edwards

      Hi Jack – the idea of Discover 2012 is to show University of Bristol research – so our exhibit was on science that we are working on in the BRIDGE (climate) and glaciology research groups. Other groups and departments did their own research topics.

      • Jack Hughes

        Either your research really does include blowing through straws (nothing surprises me any more) – or you prepared this exhibit from scratch including buying the straws.

        If you prepared it from scratch then you could have prepared all kinds of less loaded things from scratch. This could even have been an exhibit about how pH in the sea is difficult to measure and seems to show massive variation from one hour to the next in the same place.

        Or an exhibit about how buffer solutions work 🙂

  27. hunter

    As someone who has been involved in science fair projects and communicating science, I congratulate you for taking the time to work on this. A few questions and comments come to mind.
    Do you think that indulging in the hype of AGW leads to more interest in science and minds better able to critically think?
    Would it be of interest to show how the CO2 exhaled from human lungs and blown into a glass of neutral water is vastly different from large scale ocean/atmosphere processes? Ditto for the candle demonstration. Certainly it would be interesting to show a proper base line graphic demonstrating just how trivial the change the AGW community is so agitated about actually is?
    As to ocean acidification, since there is no demonstrable significant decrease in ocean pH due to human CO2, much less an acidification process that is measurable in the real world, perhaps explaining the differences between neutralization, acidification, model projections and reality would be eye opening for young minds?

  28. James P

    “Our well-loved interactive quiz about the earth, geography, weather and climate.”
    Tamsin, is that available to the rest of us, e.g. on the web?

  29. reader

    Tamsin, I find the use of the word “acid”, wrt oceans pH, is not only a misrepresentation, but it also seems intended to arouse a fear response.

  30. Jack Hughes

    I don’t like the idea of adults dumping their own anxiety and guilt onto children.

    Especially when there is a lively debate about whether the “eco problems” will ever happen or whether they will go the same way as the “population bomb” and SARS and Y2K and Mad Cow disease etc etc.

    Even if the “problems” were here and now and real it would still be wrong to dump them on children. I remember my grandparents telling me how hard they worked to HIDE the horrors of WW2 from my own parents. The horrors were very real and were happening every day (not just in a computer simulation) but the adults shielded the children.