Guest Post by Willis Eschenbach
I’m a long-time ocean devotee. I’ve spent a good chunk of my life on and under the ocean as a commercial and sport fisherman, a surfer, a blue-water sailor, and a commercial and sport diver. So I’m concerned that the new poster-boy of alarmism these days is sea-water “acidification” from CO2 dissolving into the ocean. Heck, even the name “acidification” is alarmist, because sea water is not acid, nor will it every be. What we are seeing is a slight reduction in how alkaline the sea water is.
There is a recent and interesting study in GRL by Byrne et al., entitled “Direct observations of basin-wide acidification of the North Pacific Ocean“. This study reports on the change in ocean alkalinity over a 15 year period (1991-2006) along a transect of the North Pacific from Hawaii to Alaska. (A “transect” is a path along which one measures some variable or variables.) Here is the path of the transect:
Figure 1. Path (transect) used for the measurement of the change in oceanic alkalinity.
I love researching climate, because there’s always so much to learn. Here’s what I learned from the Byrne et al. paper.
The first thing that I learned is that when you go from the tropics (Hawaii) to the North Pacific (Alaska), the water becomes less and less alkaline. Who knew? So even without any CO2, if you want to experience “acidification” of the ocean water, just go from Hawaii to Alaska … you didn’t notice the change from the “acidification”? You didn’t have your toenails dissolved by the increased acidity?
Well, the sea creatures didn’t notice either. They flourish in both the more alkaline Hawaiian waters and the less alkaline Alaskan waters. So let’s take a look at how large the change is along the transect.
Changes in alkalinity/acidity are measured in units called “pH”. A neutral solution has a pH of 7.0. Above a pH of 7.0, the solution is alkaline. A solution with a pH less than 7.0 is acidic. pH is a logarithmic scale, so a solution with a pH of 9.0 is ten times as alkaline as a solution with a pH of 8.0.
Figure 2 shows the measured pH along the transect. The full size graphic is here.
Figure 2. Measured ocean pH from the surface down to the ocean bottom along the transect shown in Figure 1.
The second thing I learned from the study is that the pH of the ocean is very different in different locations. As one goes from Hawaii to Alaska the pH slowly decreases along the transect, dropping from 8.05 all the way down to 7.65. This is a change in pH of almost half a unit. And everywhere along the transect, the water at depth is much less alkaline, with a minimum value of about 7.25.
The third thing I learned from the study is how little humans have changed the pH of the ocean. Figure 3 shows their graph of the anthropogenic pH changes along the transect. The full-sized graphic is here:
Figure 3. Anthropogenic changes in the pH, from the surface to 1,000 metres depth, over 15 years (1991-2006)
The area of the greatest anthropogenic change over the fifteen years of the study, as one might imagine, is at the surface. The maximum anthropogenic change over the entire transect was -0.03 pH in fifteen years. The average anthropogenic change over the top 150 metre depth was -0.023. From there down to 800 metres the average anthropogenic change was -0.011 in fifteen years.
This means that for the top 800 metres of the ocean, where the majority of the oceanic life exists, the human induced change in pH was -0.013 over 15 years. This was also about the amount of pH change in the waters around Hawaii.
Now, remember that the difference in pH between the surface water in Hawaii and Alaskan is 0.50 pH units. That means that at the current rate of change, the surface water in Hawaii will be as alkaline as the current Alaskan surface water in … well … um … lessee, divide by eleventeen, carry the quadratic residual … I get a figure of 566 years.
But of course, that is assuming that there would not be any mixing of the water during that half-millennium. The ocean is a huge place, containing a vast amount of carbon. The atmosphere contains about 750 gigatonnes of carbon in the form of CO2. The ocean contains about fifty times that amount. It is slowly mixed by wind, wave, and currents. As a result, the human carbon contribution will not stay in the upper layers as shown in the graphs above. It will be mixed into the deeper layers. Some will go into the sediments. Some will precipitate out of solution. So even in 500 years, Hawaiian waters are very unlikely to have the alkalinity of Alaskan waters.
The final thing I learned from this study is that creatures in the ocean live happily in a wide range of alkalinities, from a high of over 8.0 down to almost neutral. As a result, the idea that a slight change in alkalinity will somehow knock the ocean dead doesn’t make any sense. By geological standards, the CO2 concentration in the atmosphere is currently quite low. It has been several times higher in the past, with the inevitable changes in the oceanic pH … and despite that, the life in the ocean continued to flourish.
My conclusion? To mis-quote Mark Twain, “The reports of the ocean’s death have been greatly exaggerated.”
[UPDATE] Several people have asked how I know that their method for separating the amount of anthropogenic warming from the total warming is correct. I do not know if it is correct. I have assumed it is for the purposes of this discussion, to show that even if they are correct, the amount is so small and the effect would be so slow as to be meaningless.
[UPDATE] WUWT regular Smokey pointed us to a very interesting dataset. It shows the monthly changes in pH at the inlet pipe to the world famous Monterey Bay Aquarium in central California. I used to fish commercially for squid just offshore of the aquarium, it is a lovely sight at night. Figure 4 shows the pH record for the inlet water.
Figure 4. pH measurements at the inlet pipe to the Monterey Bay Aquarium. Inlet depth is 50′ (15 metres). Light yellow lines show standard error of each month’s measurements, indicating a wide spread of pH values in each month. Red interval at the top right shows the theoretical pH change which the Byrne et al. paper says would have occurred over the time period of the dataset. Photo shows kids at the Aquarium looking at the fish. Photo source.
There are several conclusions from this. First, the sea creatures in the Monterey Bay can easily withstand a change in pH of 0.5 in the course of a single month. Second, the Byrne estimate of the theoretical change from anthropogenic CO2 over the period (red interval, upper right corner) is so tiny as to be totally lost in the noise.
This ability to withstand changes in the pH is also visible in the coral atolls. It is not widely recognized that the pH of the sea water is affected by the net production of carbon by the life processes of the coral reefs. This makes the water on the reef less alkaline (more acidic) than the surrounding ocean water. Obviously, all of the lagoon life thrives in that more acidic water.
In addition, because of the combination of the production of carbon by the reef and the changes in the amount of water entering the lagoon with the tides, the pH of the water can change quite rapidly. For example, in a study done in Shiraho Reef, the pH of the water inside the reef changes in 12 hours by one full pH unit (7.8 to 8.8). This represents about a thousand years worth of the theoretical anthropogenic change estimated from the Byrne et al. paper …
The sea is a complex, buffered environment in which the pH is changing constantly. The life there is able to live and thrive despite rapidly large variations in pH. I’m sorry, but I see no reason to be concerned about possible theoretical damage from a possible theoretical change in oceanic pH from increasing CO2.
[UPDATE] I got to thinking about the “deep scattering layer”. This is a layer of marine life that during the day is at a depth of about a thousand meters. But every night, in the largest migration by mass on the planet, they rise up to about 300 meters, feed at night, and descend with the dawn back to the depths.
Looking at Figure 1, this means they are experiencing a change in pH of about 0.4 pH units in a single day … and alarmists want us to be terrified of a change of 0.002 pH units in a year. Get real.
ZP: June 22, 2010 at 5:28 pm
That was a wonderfully lucid explanation. Thanks.
/dr.bill
Dr. Bill
I’m always a bit uneasy when the well fed opine on whether the starving should eat. I am a firm believer that the best population control comes from the creation of wealth. Wealth creation starts by freeing people from subsidence agriculture, fostering a “climate” where business can flourish and access to boundless supplies of energy. (The anti green approach.) I believe in mankind and I believe in hope. (Also anti-green)
As one example- it is though that some 70 million starved under Mao -who actively sought to engage the US in nuclear war. China is now fed and beginning to attain wealth. While some current events say China is still a threat- it is not the same threat as posed by Mao. No Korea is another Mao example. History shows too many wars started by hungry people.
[REPLY – Gosh, yes. ~ Evan]
re Pat Moffitt: June 22, 2010 at 10:24 pm
I agree wholeheartedly with all of that, Pat., and I hope you weren’t referring to me as one of those who “opine on who should eat”. The official “green line” is about as odious to me as you can imagine.
/dr.bill
re Leif Svalgaard: June 22, 2010 at 11:17 pm
☺ ☺
/dr.bill
Oops! Wrong thread. 🙁
/dr.bill
Read through all the whole thread and replies – absolutely enjoyed the cut and thrust and the counters, ocean acidification is a topic that is presently being used in the Australian science and political debate. I do have a concern about the way it is being presented.
I wondered if those who are passionately for science and have expertise in the field have any such (or similar) concerns at the way this paper is being put out to the general public.
http://www.science.org.au/nova/106/106key.htm
The paper says in part
Acid test for the seas
This topic is sponsored by the Australian Government Department of Climate Change.
The basic facts on ocean acidification.
Chemists have known for a long time that a beaker of water sitting in a lab will absorb carbon dioxide from the air and turn acidic. Would it happen at a larger scale? If we greatly increased the concentration of carbon dioxide in the world’s atmosphere, for example, would the oceans become a vast acid bath? What would be the ecological effects? Over the next century or so, we are going to find out.
Increasing atmospheric carbon dioxide
For more than two hundred years, the human race has been releasing large quantities of carbon dioxide and other greenhouse gases into the atmosphere. It has been doing this in two main ways: by burning fossil fuels, such as coal, oil and natural gas, and by clearing and burning vegetation, such as forests.
Ocean acidification
Not all the carbon dioxide released
into the atmosphere stays there; some of it – about a third of total human-induced emissions – has been absorbed by vegetation during photosynthesis and a similar amount has been soaked up by the ocean. We’re lucky that it has, or global warming would be happening much more quickly than it is.
The oceans are naturally alkaline, or basic, with a pH of about 8.2. When carbon dioxide dissolves in sea water it forms carbonic acid (H2CO3), which releases hydrogen ions (H+), lowering the pH and making it more acidic. Scientists estimate that the additional carbon dioxide in the atmosphere and the subsequent absorption of some of this by the oceans has lowered oceanic pH by about 0.1 units since 1750. They also estimate that the oceans will continue to absorb the excess carbon dioxide present in the atmosphere and that oceanic pH will fall by a total of about 0.5 units by the end of this century, bringing it down to about 7.7. This is still slightly basic – so we won’t be creating a vast acid bath. But the pH scale is logarithmic, which means that even a decline of half of one unit will mean a several-fold increase in the concentration of hydrogen ions. (there is more if you actually read the paper)
My concern at the above – is this just political science being presented as a careful clever spin to aid the government justifying carbon capture or cap and trade, and is this a fair use the present position of scientific knowledge or is it just an aid to promote a form of post normal science or just propaganda.
It gives me a very uncomfortable feeling. Any advice would be helpful thanks.
KenB says:
June 23, 2010 at 5:05 am
If we left a glass of “distilled water” on the shelf it would absorb CO2 and pH would decline. Natural rain water as a result has a pH about 5.5 (Interesting to note when everyone was taught to fear acid rain that rain is always acid- there is no natural basic rain). The glass of water analogy is inherently flawed because the ocean is not distilled water but well buffered . (And you can have near shore surface water swings in pH over 0.5 units over the course of a day) Using this glass of water/CO2 analogy is inappropriate if not deceptive and says much about those pushing acidification.
We have no ability- by testing- to say what the ocean pH was a hundred years ago. And as these discussions have shown it is doubtful we can measure any decline now and ascribe those changes to CO2. This is all being driven by model assumptions-and the assumptions are always in the direction the grant funding agencies want. Studying the possibility of ocean acidification is not what we are doing- researchers are funded by government agencies to assume acidification and demonstrate its impact. That is not science.
The oceans have a number of very real problems- some like commercial overfishing- are fueled by government subsidies. (The answer to solving such problems are for governments to spend less money not more). Why believe government’s are concerned about acidification that may occur in a hundred years when they do not correct the most critical problems that we face NOW? A problem they fix by not spending money. For governments-problems are needed so they can spend money.
Smokey says:
June 22, 2010 at 9:54 am
CO2,
You may think that nitpicking everything said shows that you are intelligent and up to speed on the subject, but all it shows is insecurity covered up by ad hominem attacks [Monckton, etc].
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Ad Hominem attacks; Al Gore et al? Pot calling the kettle? Let me know one day, do you fully believe Christopher Monckton’s every word? Perhaps better to leave me guessing.
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Arbitrarily changing your original 10,000 year assertion to 20 million years is still cherry-picking. Using the time scale of the biosphere’s use of CO2 does away with the cherry-picking. I can provide you with charts similar to the one I provided up-thread, going back 4.6 billion years if it helps. They show that CO2 has been almost twenty times higher than today, in both hothouse and icehouse epochs, and during times when life thrived in much higher CO2 concentrations — without any runaway global warming.
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The cherries are getting quite old. In your case older than the earth (4.54 billion years). It seems someone else picked the cherry; http://www.sciencemag.org/cgi/content/abstract/1178296 between 180ppm (glacial) and 280ppm (interglacial) There are many more studies, just Google them yourself. When life thrived under much higher CO2? Like microbe colonies 3.5 billion years ago?
http://ris-systech2.its.yale.edu/paleo/pdf/Oldest_Fossil.pdf
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I stand by every statement I made, and while you demand citations [which I routinely gave], you provided none yourself, but only off the cuff opinions based on your scientific flawed assumptions.
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You referred to a graph, without any validating text. The graph wasn’t even related to the issue. As to the rest, an assumption on your part.
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For one example of many, you stated that: “…water vapour is not a gas, it is suspended H2O and has a cycle of hours or days.”
In fact, water vapor is a gas. Since your level of understanding is so rudimentary and filled with misconceptions, I suggest you read the WUWT archives from the beginning, so you can have an intelligent conversation without making such basic scientific errors.
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Sorry, I have better archives than WUWT. If water vapour is a gas, why don’t you call it water gas. Water’s natural state is liquid and in all meteorological references it is referred to as vapour.
We can treat it two ways; 1- when the gaseous phase is in equilibrium with the corresponding liquid or solid, or
2- when we wish to emphasize that we are talking about the gaseous phase, even though for some reason the condensed phase is considered “normal”.
Thoughtful experts refer to gaseous H2O as “water vapor” even in situations where it is nowhere near being in equilibrium with any condensed phase. Meteorology is one example, where we speak of various amounts of water vapor in the atmosphere. Astronomy is an even more extreme example, where congregations of cosmic H20 molecules are called interstellar water vapor. Since the dawn of time, these particular H2O molecules have been nowhere near saturated vapor pressure. Nobody ever speaks of water gas.
Technically and officially, “water” refers to the H2O molecule in any phase (gas, liquid, or solid) … but unofficially by long tradition “water” connotes the liquid unless otherwise specified. Water is normally a liquid.”
Hence water vapour is called a greenhouse gas, because all other gasses in the atmosphere are gasses (in their natural state). It would feel awkward if we called it a greenhouse vapour
CO2 has wasted a lot of typing, only to show that he does not understand very basic physics. It is universally accepted within science that water vapor is a gas, by definition.
CO2 states that “…water vapour is not a gas, it is suspended H2O”, then he goes into somewhat convoluted explanations trying to justify his assertion, such as, “Nobody ever speaks of water gas.” Actually, some folks refer to water vapor a “greenhouse gas,” even though the atmosphere is not a greenhouse. But water vapor is a gas, not ‘suspended’ droplets of moisture, as in fog.
A simple search produces the following definitions of gas and water vapor:
This is not nitpicking. Misunderstanding so basic a concept displays a profound lack of education in science. Anyone who believes that water vapor is not a gas needs to re-visit 5th grade science, and that is no exaggeration.
KenB says:
June 23, 2010 at 5:05 am
……..
My concern at the above – is this just political science being presented as a careful clever spin to aid the government justifying carbon capture or cap and trade, and is this a fair use the present position of scientific knowledge or is it just an aid to promote a form of post normal science or just propaganda.
It gives me a very uncomfortable feeling. Any advice would be helpful thanks.
It’s a fair presentation of the science, the speculative part is prefaced by “scientists estimate” which seems reasonable.
I have been away for a few days and haven’t been able to follow the thread. But, thanks to ZP for a very comprehensive and well laid out analysis of the limits of precision of a pH measurement. It was done far better than I could
As an approximation, 1mV equates to 0.01 pH units, so to have an accuracy of 0.0001 pH units you would need to detect a difference of one-hundreth of a millivolt. Drift and stability are shown to four decimal places, but the electrodes don’t read to that.
The calibration for this paper uses a spectrophotometric method, but that brings in other problems, which ZP does a good job of detailing also. Looking at my indicator reference book, the visual transition intervals for meta-cresol purple are only given to one decimal place, does anyone have them quoted with greater precision ?
Phil. says:
June 22, 2010 at 2:04 pm
Pressure obviously supercritical, the temperature of the CO2 would have to be over 31ºC to be a supercritical fluid.
It should be at least that when it is being emitted by a volcanic vent.
Z says:
June 23, 2010 at 12:21 pm
Phil. says:
June 22, 2010 at 2:04 pm
“Pressure obviously supercritical, the temperature of the CO2 would have to be over 31ºC to be a supercritical fluid.”
It should be at least that when it is being emitted by a volcanic vent.
Yeah you’d think so, it’s subsequent history would be interesting since you’d have simultaneous cooling an dissolution (both ways).
PAEH says:
June 23, 2010 at 11:36 am
I have been away for a few days and haven’t been able to follow the thread. But, thanks to ZP for a very comprehensive and well laid out analysis of the limits of precision of a pH measurement. It was done far better than I could
As an approximation, 1mV equates to 0.01 pH units, so to have an accuracy of 0.0001 pH units you would need to detect a difference of one-hundreth of a millivolt. Drift and stability are shown to four decimal places, but the electrodes don’t read to that.
The method doesn’t use electrodes, it’s entirely spectrophotometric.
Bill S says:
June 22, 2010 at 11:23 am
I was beginning to lose hope that someone would notice …
w.
Ken Peterson says:
June 22, 2010 at 2:45 pm
Thanks, Ken. So the slope is -.000004 pH units per year, and the water quality folks say that shows a longterm decrease? Someone should tell them about the concept of statistical significance, as that slope is most assuredly not statistically different from zero.
w.
Z says:
June 22, 2010 at 1:33 pm
Yeah, I thought about that, but pH varies linearly with pCO2. Assuming that the driving force is the change in atmospheric CO2 (and thus pCO2), and that the increase in atmospheric CO2 is linear, we can divide one into the other. Or at least that was how my logic went, let me know if I’m wrong.
w.
ZP says:
June 22, 2010 at 5:28 pm
ZP, thank you for a most lucid and readable explanation of the issues involved in the determination of the pH. I had suspected their data as soon as I read the claims of accuracy to 0.001 pH units, but knowing nothing of the question of the accuracy of pH meters, I put it down to my naturally suspicious and unbelieving character.
So thank you for restoring my faith in the fallibility of scientists, much appreciated.
w.
Willis Eschenbach says:
June 24, 2010 at 2:40 am
Yeah, I thought about that, but pH varies linearly with pCO2.
Willis, according to:
http://www.sciencemag.org/cgi/content/full/286/5447/2043a#E1
[H+]^2 is proportional to pCO2 so that would give pH varies as ln(√CO2)
Might not make much difference for small changes in CO2 of course.
Phil. says:
June 24, 2010 at 7:13 am
Yes, curiously I used that same paper as a reference. You are correct that pH varies as ln(√CO2). However, over the range in question, the graph in the paper shows that the relationship is only trivially different from a straight line.
Thanks,
w.
Willis Eschenbach says:
June 24, 2010 at 10:38 am
Phil. says:
June 24, 2010 at 7:13 am
Willis Eschenbach says:
June 24, 2010 at 2:40 am
…….
“[H+]^2 is proportional to pCO2 so that would give pH varies as ln(√CO2)
Might not make much difference for small changes in CO2 of course.”
Yes, curiously I used that same paper as a reference. You are correct that pH varies as ln(√CO2). However, over the range in question, the graph in the paper shows that the relationship is only trivially different from a straight line.
Indeed, the advantage of using logs!
Implies that a factor of 2 in pCO2 would give an increase of 1.4X in [H+], -0.15 in pH.
Phil in your reply, you deliberately ignored the first sentence at the start of my last paragraph. So I will repeat it here :
“The calibration for this paper uses a spectrophotometric method, but that brings in other problems, which ZP does a good job of detailing also. ”
You obviously intended to misrepresent my statement. I also notice that you have completely ignored the entire post by ZP, which specifies with great clarity and articulation, why the pH cannot be measured to 4 decimal place precision either by electrodes or spectrophotometry. Why have you chosen to do this ?
To recap from ZP, even if they were to use a spectrophotometric system for detection of [H+] based on theoretical pKa calculations on a dye, at some point in the real world they would have to compare the theoretical prediction against an actual electrode reading. And the point of my last point was that to do that to 4 decimal place precision (aside from all the other practical limitations that ZP discusses), the electrode would have to be capable of accurately and precisely distinguishing one hundredth of a millivolt. If you can’t compare your theoretical prediction to an actual reading then you can’t claim the precision.
I will not comment on your debate about the certainty that the same batch of dye could have been used 15 years apart to avoid the issue of differing impurities affecting the accurate repeatability, or accepting corrections that are greater than the stated precision, I believe other commentators have shown how erroneous those beliefs to be.
But, I will go back to one of you earlier posts where you pulled some information from an internet site, carbonic acid is , well an acid, whereas the bicarbonate ion will buffer saline in the alkaline region above pH 7 !
Willis you missed the “your either on the bus or off the bus” Acid Test comment
There’s an interesting article I stumbled across today, which bears directly on this issue and supports my contention that the so-called “acidification” is a non-issue.
Also:
Pat Moffitt says:
June 24, 2010 at 6:04 pm
Sorry, I saw it but didn’t comment on it because I’m either in my mind or out of my mind …
Please can someone help: I’m just trying to work out how Willis calculated the number of years for Hawian waters to reach Alaskan pH levels based on the quoted rates of change. Is the following correct:
The existing Hawaii to Alaska pH levels are quoted as 8.05 to 7.65. A pH difference of -0.4. Due to the logarithmic scale this corresponds to a factor of 10^-0.4 = 0.398 reduction in alkali concentration.
The GRL report claims the 15-year man-made pH change is -0.012 (= factor of 0.973)
OK. Now how to calculate the number of years ‘Q’ to reach Alaskan levels.
Is it 0.973 ^ (Q/15) = 0.398 ?? In which case, by interating on my calculator I get Q = 33 x 15 = 495 years?
Next question: Is it reasonable to assume each yearly reduction will be a constant factor – or would it be more accurate to assume a fixed reduction every year.
eg. (Q/15) * (1-0.973) = 0.398 so Q = 221 years ??
Either way I agree it’s not much to worry about when you consider the effect of deepwater mixing.