The Electric Oceanic Acid Test

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.

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timetochooseagain

How exactly did humans cause pH to increase at about 1000 meters between 25 degrees North latitude and 30 degrees North latitude? This “human induced change”-is it really just a difference of the beginning of trend lines and the end? Which basically assumes that the only way the ocean’s pH can change, even in individual locations, is because of people. That strikes me as ridiculous.

R Shearer

Why is the pH lower at depth?

higley7

Given how little we know about what is the real human contribution to atmospheric CO2, I find it incredible that the authors can begin to discuss a pH change attributable to human activity. They MUST be expressing an opinion or speculation here as they have no definitive means of determining a human influence.
As the equilibrium of bicarbonate/carbonate and carbonate and calcium ions/calcium carbonate is temperature dependent and complicated by the lower solubility of calcium carbonate in warm water versus cold, this is a more complicated system than is presented here. The two equilibrium would work against each other in response to temperature changes.
Thus, a wonderful observation of the oceans as a system about which we still have much to learn, but a meaningless discussion of human effects.

pH varies all over the place locally, too. [scroll down for charts]

Steve Oregon

“because sea water is not acid, nor will it ever be”
ever

mike

interesting. i didn’t read the paper but how do we assume any ‘human inducement’? but i get the point.

fred houpt

Not related, but I just saw this note on the BBC.
http://news.bbc.co.uk/2/hi/science_and_environment/10342318.stm
I don’t know whether to laugh or cry. I will say that I am making an effort to read the entire and very well written ” Global Warming Advocacy Science: a Cross Examination” by Jason Scott Johnston, U of Penn, May 2010, uploaded to this site a few days ago.
As the rain blasts start to pummel my house….I bid you a warm good evening.

dearieme

The polynesians used to navigate by (among other things) tasting the sea water. I had assumed that they were tasting for salinity or for microbial life; could they have been tasting for alkalinity too?

Another in a string of excellent articles, Willis.
When you hot… you HOT! [apologies to the late, great Jerry Reed]

And the *same* sea creatures flourish in both Hawaii and Alaska? Without any adaptation that might take a few million years? And our emissions aren’t currently accelerating?
timetochooseagain: the paper explains how they distinguished natural changes from anthropogenic changes. Natural variability is shown in the paper’s figure 3. The scale is greater than the anthropogenic variation (figure 4), but note that natural variability will add up to zero over longer time scales, anthropogenic variability will not.

Ian W

This is what you would expect from Henry’s law and the temperature gradient between Hawaii and Alaska. The difference at depth is almost certainly driven by the vertical temperature gradient.

Joe Lalonde

I enjoy reading your scientific discoveries and analysis as well :~)

Hey! Chemistry! My field. Awesome.
First, when CO2 dissolves in water, you get carbonic acid.
CO2 + H2O –> H2CO3
The dissolved gas concentrations are higher in colder water and higher pressures, which explains the pH closer to 7.0. This is counter-intuitive, as people think warmer solutions dissolve more stuff (which they do). But if you heat up any liquid, like a pot of water on the stove, you start seeing bubbles. That’s dissolved gas escaping as the temperature increases. So, in warmer waters, there’s less dissolved CO2, so the pH will be higher as there’s less carbonic acid.
So this “acidification of the oceans” meme is rather odd. As the global temperature increases, so does the surface ocean temperature. And when that happens, the surface can hold less CO2, which means it’s not going to be as acidic. I see the system as self regulating and something not to worry about.

etudiant

Excellent post.
Provides a real informational increment and helps put the ocean acidification claims into perspective.
It would be interesting to have some explanation as to why the ocean is alkaline in the first place, as the inputs from the atmosphere, including CO2 as well as nitric oxydes from lightning are acidic.
Is the biological input in the tropics providing the alkalinity observed?

Ed MacAulay

Now what if a subsea volcano or vent was slowly releasing gases and other materials?. Would it release sulfates, carbon dioxide or other pH modifiers? How would one separate that background level from the anthropogenic?

Robert M

Joel,
Has it occurred to you that mankind has already burned a significant percentage of all the fossil fuels available to mankind, and our contribution to ocean alkalinity is insignificant. Over the course of the next 400 years any effects caused by mankinds C02 emissions will peak and fade away without causing ANY affects upon sea life.

Jimbo

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.


This is how I look at claims of “unprecedented” rise in [….insert climate claim…]. Whenever you look back in time we know we have had higher c02 levels than present, we know we have had higher global mean temperatures than the present and yet no runaway boiling of the planet. We are still here!
Acid Test
Are oceans becoming more acidic and is this a threat to marine life?
Biological Effects of "Ocean Acidification"
In CO2-rich Environment, Some Ocean Dwellers Increase Shell Production
Phytoplankton Calcification in a High-CO2 World
Modern-age buildup of CO2 and its effects on seawater acidity and salinity
“This paper’s results concerning average seawater salinity and acidity show that, on a global scale and over the time scales considered (hundreds of years), there would not be accentuated changes in either seawater salinity or acidity from the observed or hypothesized rises in atmospheric CO2 concentrations. ”
And finally here is a blogger’s view of the new scare or in other words funding opportunity. :o)

Ed Caryl

DocattheAutopsy,
If I’ve got this straight, points in the ocean that are acidifying must be cooling?

eo

The relationship betweern pH and alkalinity is not straight forward because of the buffering effect of carbon dioxide/carbonate/bicarbonate ions in water as could be shown when a carbonate solution is titrated. There is more photosynthesis at the warmer surface water closer to the tropics that removes the carbon dioxide from the water and also carbon dioxide is less soluble. As the water pressure increases, there is more dissolved carbo dioxide. As corals are made mostly of calcium carbonate, people often think corals reduces the carbon dioxide in seawater. However, for every calcium ions there are two ions of bicarbonate. To form one molecule of calcium carbonate, one morelcule of carbon dioxide is added by the coral to the seawater.

Mike Davis

By observing one fourth of an approximate 60 year ocean atmosphere oscillation they know all there is to know about the ocean PH balance. WOW! How much has it changed naturally over the last 10,000 years or even the last 800,000 years? I wonder what the human population along that transect of the ocean?

latitude

“‘DocattheAutopsy says:
And when that happens, the surface can hold less CO2, which means it’s not going to be as acidic””
and they claim that the slight warming right now, at our present CO2 levels, is causing the ocean to release CO2.
But at even higher CO2 levels, with even more warming, the ocean is supposed to somehow take up and hold more CO2 – making it less alkaline.
Just checked the pH in my front yard, I live on a rock in the middle of the Caribbean, it’s 8.4 Haven’t noticed any sea rise either.

Geoff Sherrington

Two linked papers from New Zealand take some account of the ocean as a host for biota. I have read but not studied these, but on a quick read I cannot see any immediate objections, except to the pronunciation of “fish and chips.”
My Internet search was for terms including titration of ocean water with CO2 and pH change. There are other interesting papers. Not many deal with direct electrode pH measurement and titration with CO2, which one would have thought to be the essential starting point of any investigation of the broader topic.
http://www.seafriends.org.nz/issues/global/acid.htm
http://www.seafriends.org.nz/issues/global/acid2.htm
These papers give some answers to some questions above. Well worth a study. See especially the annual variation in the second paper under “BATS” from the Bermuda area, bottom graph for pH.

Jimbo

Please Willis Eschenbach or anyone else more qualified than me take a look at the following story from the BBC. Others as well as I have read it and makes us want to cry!!!

“Ancient climate change ‘link’ to CO2”
“A “global pattern” of change in the Earth’s climate began 2.7 million years ago, say scientists. ”
http://news.bbc.co.uk/2/hi/science_and_environment/10342318.stm

latitude

“”Joel says:””
Joel, rains, wind, storms, tides, upwellings, El Nino/La Nina, etc can cause very rapid, almost instant, changes in pH, salinity, temperature, Ca and carbonate levels, etc etc
Everything out there has evolved to deal with that, nothing out there is that delicate.
They ship corals all over the world in plastic fish bags, acclimate them to a holding facility, acclimate them to shipping water, acclimate them to a new warehouse, acclimate them again to a new pet shop, acclimate them again to someone’s aquarium. And all along the way their pH go up and down and all over the place.

DocattheAutopsy says:
June 19, 2010 at 6:40 pm
Hey! Chemistry! My field. Awesome……….
So this “acidification of the oceans” meme is rather odd. As the global temperature increases, so does the surface ocean temperature. And when that happens, the surface can hold less CO2, which means it’s not going to be as acidic. I see the system as self regulating and something not to worry about.

However you’ve forgotten that the equilibrium concentration of CO2 in the surface water is also dependent on the pCO2 in the atmosphere which is being steadily increased by fossil fuel combustion.

Baa Humbug

R Shearer says:
June 19, 2010 at 5:58 pm
Why is the pH lower at depth?

Rocks

Jeff

Robert M,
ah, a Peak Oil fan … we haven’t even scratched the surface of the fossil fuels available to us around the globe. Have you noticed that there have been huge, HUGE oil and natural gas discoveries in the last year …. everytime we really look we find more … we have 200-300 years of coal in the US alone …
since we could burn it all and still not effect global temperatures I’m not really worried …

Fraizer

A couple of questions for our alarmist friends:
1) What is the ultimate carrying capacity of an infinitely buffered alkaline solution for an acid gas?
2) Where does limestone come from?

JDN

I’m ready for a solar eruption (because I believe what NASA tells me). How will that affect ocean pH? 🙂
Too much speculation?

Phil. says:
“However you’ve forgotten that the equilibrium concentration of CO2 in the surface water is also dependent on the pCO2 in the atmosphere which is being steadily increased by fossil fuel combustion.”
Even if true, that is bad, because …?

Dr A Burns

Excellent post apart from the assumption, without any form of justification, that humans have induced a pH change.

timetochooseagain

Joel-The changes still seem odd to me. If you don’t have the answer, does anyone else have a plausible explanation for why there is an increase of pH with time at a depth of 1000 meters between 25 N and 30 N? And another question, this one specifically for you Joel: What do you consider “longer timescales”? Centuries? Millennia? Millions even billions of years? And do you believe that Nature is static over that timescale? Because it isn’t over any timescale. Even over billions of years, the Sun gets brighter and eventually expands to engulf us, later sloughing off it’s outer layers in a huge explosion and becoming a dim white dwarf. I’m not trying to make a point, it’s just that I don’t really think that “natural variability will average out to zero” is something that can be said to be accurate. On the other hand, anthropogenic effects will amount to zero in billions of years. Am I being pedantic? Yes. But that’s the way I am.

Jim Clarke

Joel says:
June 19, 2010 at 6:26 pm
“…but note that natural variability will add up to zero over longer time scales, anthropogenic variability will not.”
Is this one of those untrue statements that has no real meaning and is only designed to frighten? Yes…I believe it is!
Nothing in nature is ‘sustainable’ if one considers long enough time periods. Nothing in nature is ‘balanced’ unless one considers only very short time periods, and even that is a stretch. The nature of Nature is change. Get use to it. The rest of nature has no problem with it, only semi-educated, wealthy Westerners seem to think the world is ‘broken’ if it is not the way it was when they were young.

rbateman

And they wonder why AGW credibility is going down the drain so quickly.
Endless streams of nebulous claims (like ocean acidification) will do that.
Right up there with the 10 foot sea-level rise currently lapping the steps of Capitol Hill.

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.
But not the same life!
Case in point, the PETM mass extinction involved a jump in CO2 and temperature and an associated extinction of about 95% of marine lifeforms. It took ~80,000 years for the oceanic chemistry to stabilize.

R Taylor

Clear and concise. Let’s hope it encourages a few more to be NOT ON THE BUS.

DR

http://scienceandpublicpolicy.org/images/stories/papers/originals/soon_carbon_myopia_talk.pdf

“Most of these experiments used
semi-continuous cultures, in which
the carbonate system was modified
by the addition of acid and/or base to
control pH.” —Debora Iglesias-Rodroguez et al. (2008)

“By geological standards, the CO2 concentration in the atmosphere is currently quite low. It has been several times higher in the past…”
Added CO2 at the surface (from the atmosphere) should be making the surface water less alkaline than successively deeper waters, but the charts show just the opposite. So, with deeper water being less alkaline than surface water, doesn’t that imply that CO2 is coming out of the ocean and into the atmosphere? Geologically low levels of atmospheric CO2 are “sucking” the CO2 out of the water (pardon the lack of scientific jargon here.)
Isn’t this what we would expect? First temperatures rise, and then CO2 goes up, in this case from the ocean. Isn’t this paper yet another disproof that rising atmospheric CO2 causes rising temperatures?

Pat Moffitt

An amazing claim from this paper:
“The component of pH change associated with penetration of anthropogenic CO2 into the upper ocean (ΔpHant, Figure 4) is given by the difference between total pH change (Figure 2) and the pH change attributable to variations in respiration and ocean ventilation (Figure 3). Evidence of anthropogenic influence is seen to depths of 150 m along the entire section. In this zone, ΔpHant varies between −0.01 and −0.03 with a mean value of −0.023 (±0.001). Between 22° and 38°N, anthropogenic acidification extends to more than 500 m and the −0.02 contour extends to more than 400 m.”
What they are saying is they precisely know the oceanic ventilation and respiration pH effects and how these mechanism change along their transect (plus the data set and instrument corrections) such that they can confidently calculate a 0.023 pH decline from AGW CO2 in some regions. Who knew we had such command of oceanic ventilation and respiration?

dumbass

So that is why you dont get coral reefs at the arctic?

Pat Moffitt

As someone who has also spent most of his life on, near or in the ocean- my great concern is that ocean acidification will hijack the very real problems we have with our keystone oyster populations. Oysters populations have collapsed as the result of physical habitat alteration (due to harvest) and importantly two devastating diseases Dermo and MSX. To give some idea how important oysters are in coastal ecosystems it is thought that prior to the collapse oysters filtered the entire contents of the Chesapeake every 3 days. Despite their keystone status the resources available to address this problem have been paltry at best. (Oysters and disease just don’t make good copy, fund raising or law suits.) Now the oysters will have to find a way to survive the new dictate that all shellfish problems must be caused by CO2.

Derek B

Complaining about calling a drop in alkalinity acidification is kind of silly. What else would you call it? You might as well complain that a drop in temperature from 100 degrees to 99 should not be called cooling.
You cannot argue that the organisms will cope in general because there are already organisms coping with 7.25. These are at different latitudes, so unlikely to be the same species. Likely the equatorial species could cope given long enough to evolve, but we don’t know how long that requires. And the species at higher latitudes will be exposed to acidities for which there are no extant marine precedents.
As for the back-of-the-envelope calculation about timescales of further acidification, it is contradicted by several more painstaking estimates: http://en.wikipedia.org/wiki/Ocean_acidification#Acidification. This is probably a lot to do with the fact that you have not taken into account that the CO2 level in the atmosphere is higher than at any time for a couple of hundred years, so the rate of acidification is higher than at any time in that period too – and increasing.
Sorry – not up to your usual standard.

Paul Benkovitz
Mike Hall

The deep ocean (below 1,000 m) holds the largest amount of carbon dioxide than any other planet earth compartment – more then all the atmosphere (by orders of magnitude), more then all terrestrial carbon, more then all the fossil fuel burnt and more then all known fossil fuel reserves in the world. Even the IPCC reports agree with this. If you want to get very afraid, then the end is near if ever the deep ocean water masses erupt to the surface. Indeed, some published papers suggest this may have happened in the ancient past and caused massive changes to the earth. Basically the deep sea is under enormous pressure and very cold – water can hold much much more dissolve gas at pressure and when cold. So when the deep sea upwells to the surface it is like opening a bottle of carbonated drink – under pressure and in the fridge. There are many areas of the earth’s ocean that degass carbon dioxide to the atmosphere. It will probably prove that the concerns about ocean ‘acidification’ will be vastly exaggerated but it is a cause that is at least worth a look. Without question, some of the increased concentration of carbon dioxide in the air goes into solution in water, with >70 of the surface with an gas:water interface, some, of course, will dissolve into the water. So far the scientific jury is still very much out on the issue – so far some evidence for and some against for the jury. If a betting man, it will prove a very minor issue with respect to all the other problems that face the planet.

dr.bill

Phil.: June 19, 2010 at 7:53 pm
But not the same life!  Case in point, the PETM mass extinction involved a jump in CO2 and temperature and an associated extinction of about 95% of marine lifeforms. It took ~80,000 years for the oceanic chemistry to stabilize.

“Stock check in Aisle 4, please. Supply of Depends getting low.”
/dr.bill

wayne

A mere -0.02 ph? But these are just alarmist “scientists”. Maybe some of the readers here might want to get a first hand experience of what a real scientist is actual like, that way they can spot these “alarmist climatologists” a mile away too:
Just sat through 4 – 1½ hour lectures by one of my favorites, late Dr. Richard Feynman, on his quantum-electrodynamics (QED) theory, explained in exquisite detail with only chalk in a manner that anyone half knowledgeable in basic physics and algebra can follow. Staying away from complex numbers and mind twisting mathematics he lays out the theory and many examples only using simple pointers (vectors) and logic.
Those more knowledgeable will recognize that his simple pointers and simple add and multiply operations are actually describing the complex number underlying this theory though he never fesses up to this until late in the series. So even the more experienced can get some deep insight too by using some upward mental translation.
I have never seen a lecture given in such clarity, brilliant and so full of humility with a sprinkle of skeptism, but above all, he lets the data and logic guide him always.
Also this is a great view of who Isaac Newton really was and how he thought.
Richard Feynman describing the QED theory of “nearly everything”
http://www.vega.org.uk/video/subseries/8
If you like science and physics, this one is guaranteed to please!

flyfisher

One other thing to consider: what is the standard error of their equipment? I’d be astounded if their measurement device was accurate below 0.01 pH Units. Their measurements only go to 3 sig figs, so a difference of even 0.03 pH over 15 years is pretty much zero to no change considering error.

chris y

Willis- Thanks for another interesting post. It once again shows the paucity of ocean pH data available for analysis. I wonder if anyone would be successful at publishing a paper that compared two satellite sweeps on March 15, separated by 15 years (say 1995 and 2010), measured along a single 5 degree wide longitudinal stripe that only includes some of the Northern hemisphere, and drawing any sort of conclusion about anthropogenic influences (or lack thereof) on lower tropospheric temperatures.
I find it remarkable that a climate science paper can claim, without resorting to a database of at least 50 years of observational pH data sampled at least 4 times per year and with some (any) spatial coverage, draw the conclusion that anthropogenic emissions of CO2 are responsible for a 0.01 – 0.02 pH change over a 15 year period. It is remarkably sad.

Peter

“pH slowly decreases along the transect, dropping from 8.05 all the way down to 7.65. This is a change in pH of 0.5.”
Isn’t this a change in pH of 0.4?

Mooloo

This is probably a lot to do with the fact that you have not taken into account that the CO2 level in the atmosphere is higher than at any time for a couple of hundred years
Not really. CO2 concentration is increasing more or less arithmetically, whereas pH is a logarithmic scale. So if CO2 concentration were the only factor in ocean pH, CO2 would have to increase by 10 times to give a pH increase of 1.
But, as others have pointed out, increasing temperature acts to decrease the solubility of CO2. Increasing CO2 concentrations will also likely increase carbonate shell drop out by organisms. So we will really have to get cracking with CO2 production to affect the oceans by partial pressure of the gas.
Humans may yet kill everything in the sea by over-fishing and pollution. Those are major concerns to me. CO2 acidification is an unnecessary distraction from the real issues.
Complaining about calling a drop in alkalinity acidification is kind of silly.
I beg to differ. It sets up the assumption in the mind of many that read it that the oceans were neutral and are rapidly being acidified. We here know that is wrong, but it is the obvious reading to a scientifically ignorant person. It raises the scare content.
It is similar to the description of the “warm” temperatures in the Arctic. If you don’t read too deeply you get the impression that the temperatures are above freezing.
Politicians are routinely rubbished for using excessively scary language where a technical person (economist, say) might use guarded terms. So it should be in climate science. Use the right terms and avoid the emotive rubbish.