Claim: Modern Ocean Acidification Is Outpacing Ancient Upheaval, Study Suggests

Rate May Be Ten Times Faster, According to New Data

The deep-sea benthic foram Aragonia velascoensis went extinct about 56 million years ago as the oceans rapidly acidified. (Ellen Thomas/Yale University)

From Lamont-Doherty Earth Observatory: Some 56 million years ago, a massive pulse of carbon dioxide into the atmosphere sent global temperatures soaring. In the oceans, carbonate sediments dissolved, some organisms went extinct and others evolved.

Scientists have long suspected that ocean acidification caused the crisis—similar to today, as manmade CO2 combines with seawater to change its chemistry. Now, for the first time, scientists have quantified the extent of surface acidification from those ancient days, and the news is not good: the oceans are on track to acidify at least as much as they did then, only at a much faster rate.

In a study published in the latest issue of Paleoceanography, the scientists estimate that ocean acidity increased by about 100 percent in a few thousand years or more, and stayed that way for the next 70,000 years. In this radically changed environment, some creatures died out while others adapted and evolved. The study is the first to use the chemical composition of fossils to reconstruct surface ocean acidity at the Paleocene-Eocene Thermal Maximum (PETM), a period of intense warming on land and throughout the oceans due to high CO2.

“This could be the closest geological analog to modern ocean acidification,” said study coauthor Bärbel Hönisch, a paleoceanographer at Columbia University’s Lamont-Doherty Earth Observatory. “As massive as it was, it still happened about 10 times more slowly than what we are doing today.”

The oceans have absorbed about a third of the carbon humans have pumped into the air since industrialization, helping to keep earth’s thermostat lower than it would be otherwise. But that uptake of carbon has come at a price. Chemical reactions caused by that excess CO2 have made seawater grow more acidic, depleting it of the carbonate ions that corals, mollusks and calcifying plankton need to build their shells and skeletons.

In the last 150 years or so, the pH of the oceans has dropped substantially, from 8.2 to 8.1–equivalent to a 25 percent increase in acidity. By the end of the century, ocean pH is projected to fall another 0.3 pH units, to 7.8. While the researchers found a comparable pH drop during the PETM–0.3 units–the shift happened over a few thousand years.

“We are dumping carbon in the atmosphere and ocean at a much higher rate today—within centuries,” said study coauthor Richard Zeebe, a paleoceanographer at the University of Hawaii. “If we continue on the emissions path we are on right now, acidification of the surface ocean will be way more dramatic than during the PETM.”

The study confirms that the acidified conditions lasted for 70,000 years or more, consistent with previous model-based estimates. “It didn’t bounce back right away,” said Timothy Bralower, a researcher at Penn State who was not involved in the study. “It took tens of thousands of years to recover.”

From seafloor sediments drilled off Japan, the researchers analyzed the shells of plankton that lived at the surface of the ocean during the PETM. Two different methods for measuring ocean chemistry at the time—the ratio of boron isotopes in their shells, and the amount of boron –arrived at similar estimates of acidification. “It’s really showing us clear evidence of a change in pH for the first time,” said Bralower.

What caused the burst of carbon at the PETM is still unclear. One popular explanation is that an overall warming trend may have sent a pulse of methane from the seafloor into the air, setting off events that released more earth-warming gases into the air and oceans. Up to half of the tiny animals that live in mud on the seafloor—benthic foraminifera—died out during the PETM, possibly along with life further up the food chain.

Other species thrived in this changed environment and new ones evolved. In the oceans, dinoflagellates extended their range from the tropics to the Arctic, while on land, hoofed animals and primates appeared for the first time. Eventually, the oceans and atmosphere recovered as elements from eroded rocks washed into the sea and neutralized the acid.

Today, signs are already emerging that some marine life may be in trouble. In a  recent study led by Nina Bednaršedk at the U.S. National Oceanic and Atmospheric Administration, more than half of the tiny planktic snails, or pteropods, that she and her team studied off the coast of Washington, Oregon and California showed badly dissolved shells. Ocean acidification has been linked to the widespread death of baby oysters off Washington and Oregon since 2005, and may also pose a threat to coral reefs, which are under additional pressure from pollution and warming ocean temperatures.

“Seawater carbonate chemistry is complex but the mechanism underlying ocean acidification is very simple,” said study lead author Donald Penman, a graduate student at University of California at Santa Cruz. “We can make accurate predictions about how carbonate chemistry will respond to increasing carbon dioxide levels. The real unknown is how individual organisms will respond and how that cascades through ecosystems.”

Other authors of the study, which was funded by the U.S. National Science Foundation: Ellen Thomas, Yale University; and James Zachos, UC Santa Cruz.

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Steve in Seattle

This cannot be : a recycle of all the previous catastrophic ocean acidification “garbage” fear mongering studies. Simply shuffle the positions of words such as “could”, “perhaps”, “possibly”, and, of course, “estimate”. The watermelons just keep recycling this trash, and the left of liberal media spoon feed it to the 47 percent too dumb, but allowed to vote anyway.
As I have posted before, this will never end, I see nothing but very bad, ahead.

Rhoda Klapp

You mean all the sea organisms today are the ones which survived the last event and are therefore capable of accepting similar levels?
You mean we wouldn’t be here at all if the last event had not happened?

Richard111

” the pH of the oceans has dropped substantially, from 8.2 to 8.1–equivalent to a 25 percent increase in acidity”
Really???

“she and her team studied off the coast of Washington, Oregon and California showed badly dissolved shells.”
Probably right around spreading centers where a lot of acidic water is being pumped into the ocean.

Jeff Szuhay

A pH of 7.8… Uh, that’s still alkaline. Not acid until it goes below 7.0.
Where’s the news here?

thegriss

“have made seawater grow more acidic”
Utter BS..
The seas ARE NOT acid and they WILL NEVER be acid.
Since they are not acidic, they cannot become more acidic.
They may have become a tiny bit LESS BASIC or LESS CAUSTIC
,
but that is not the same thing, and may I fact be a GOOD THING…..
just like everything else to do with increasing atmospheric CO2.
And I would love to see how they measured the PH of sea water to the nearest 0.1 , 150 years ago. !!

Peter Miller

Just like in the recent past, the warming in the PECM preceded the increase in CO2 levels.
As usual, alarmists don’t like facts getting in the way of their theories.
http://adsabs.harvard.edu/abs/2007Natur.450.1218S

kadaka (KD Knoebel)

In the last 150 years or so, the pH of the oceans has dropped substantially, from 8.2 to 8.1–equivalent to a 25 percent increase in acidity. By the end of the century, ocean pH is projected to fall another 0.3 pH units, to 7.8.
Better check the promulgation and evolution of The Message.
http://ocean.nationalgeographic.com/ocean/critical-issues-ocean-acidification/
(no date, apparently dynamic page, subject to change)

(…) Over the past 300 million years, ocean pH has been slightly basic, averaging about 8.2. Today, it is around 8.1, a drop of 0.1 pH units, representing a 25-percent increase in acidity over the past two centuries.

The oceans currently absorb about a third of human-created CO2 emissions, roughly 22 million tons a day. Projections based on these numbers show that by the end of this century, continued emissions could reduce ocean pH by another 0.5 units. (…)

So drop about fifty years from the dramatic rise of Ocean Neutralization for a more worrisome rate.
But the new work says the pH drop by 2100 has been drastically cut, down to 0.3 pH from 0.5.
There is hope! Human impact will not be as bad as was thought!
From 2008, article, shouldn’t change:
http://www.scientificamerican.com/article/rising-acidity-in-the-ocean/

(…) The pH of seawater has remained steady for millions of years. Before the industrial era began, the average pH at the ocean surface was about 8.2 (slightly basic; 7.0 is neutral). Today it is about 8.1.
Although the change may seem small, similar natural shifts have taken 5,000 to 10,000 years. We have done it in 50 to 80 years. Ocean life survived the long, gradual change, but the current speed of acidification is very worrisome. Emissions could reduce surface pH by another 0.4 unit in this century alone and by as much as 0.7 unit beyond 2100. (…)

So what they used to say we filthy humans did in 50 to 80 years, we perversions of the natural order now did in 150 to 200 years, we took three times longer.
The “facts” are getting less alarming, humans aren’t as badly the horrendous destroyers of innocent planets we used to be.
Things are really looking up!

jones

Oh my God noooooo….It’s even worserer than we thought.

Phil

From A Basic History of Acid—From Aristotle to Arnold:

Clarity was brought to the field when, in the 1890s, Svante August Arrhenius (1859–1927) finally defined acids as “substances delivering hydrogen cations to the solution” and bases as “substances delivering hydroxyl anions to the solution”.
………
It was the work of Hermann Walther Nernst (1864–1941) that, in 1889, gave the theoretical foundation for the use of electrode potential to measure the concentration of an ion in solution. With Arrhenius’s definition of acidity as the result of hydrogen ion concentration, it was a small step to create a scale of acidity based on the results of electrode potential.
……….
In his 1909 paper in Biochemische Zeitschrift, S. P. L. Sørenson developed a new colorimetric assay for acidity. But more importantly, he defined the concept of expressing acidity as the negative logarithm of the hydrogen ion concentration, which he termed pH.
…………
in 1934, when Arnold O. Beckman invented the acidimeter based on the request of an old friend, Glen Joseph, who worked for the California Fruit Growers Association
(www.geocities.com/bioelectrochemistry/beckman.htm).
(emphasis added)

There is no global database of pH variability in the oceans. Dore et al. (2009) uses data from station ALOHA to document a “decreasing trend” of pH, “which is indistinguishable from the rate of acidification expected (emph. added) from equilibration with the atmosphere.”
From:
Dore et al. (2009) Physical and biogeochemical modulation of ocean acidification in the central North Pacific. PNAS July 28, 2009 vol. 106 no. 30:12235–12240

Despite the urgency of the ocean acidification problem, there are few available data sets directly documenting its long-term (decadal to interdecadal) rate or its shorter-term (seasonal to interannual) variability. Repeat hydrography has been used to document a decadal increase in the inventory of DIC in the Pacific (8); however, the technique has not yet been applied to the detection of pH changes. Long-term trends in pCO2oce globally have also been documented from large data synthesis efforts (9), but these results do not directly address pH and are confined to the surface layer.
(emphasis added)

From (Reference 9 in quote above):
9. Takahashi T, et al. (2009) Climatological mean and decadal change in surface ocean
pCO2, and net sea-air CO2 flux over the global oceans. Deep-Sea Res II 56:554–577.

A climatological mean distribution for the surface water pCO2 over the global oceans in non-El Niño conditions has been constructed with spatial resolution of 4° (latitude) x 5° (longitude) for a reference year 2000 based upon about 3 million measurements of surface water pCO2 obtained from 1970 to 2007.
Multi-year composite maps summarizing the sampling locations and the number of months, in which at least one measurement was made since 1970 in each box, are shown in Figs. 1A and B. The latter map shows that, of a total of 1759 boxes, about 30% of the boxes have measurements spanning 6 or more months, and 50% of the boxes have measurements spanning 3 or less months. While most boxes in the Northern Hemisphere have observations in 6 or more months, many in the Southern Hemisphere oceans south of 20°S have data only in 3 or less months. The Drake Passage areas that are being investigated as part of the Long Term Ecosystem Research (LTER) program along the Antarctic Peninsula are the only southern high-latitude boxes that have 12-month data.
(emphasis added)

David Schofield

Seriously. Can someone explain to me how the warming oceans take up this carbon dioxide whilst at the same time giving it off??
http://www.newscientist.com/article/dn20413-warmer-oceans-release-co2-faster-than-thought.html#.U47SPdq9KSM

Andrew N

pH is a logarithmic scale, so to say that it is 25% more acidic because it has moved by 0.1 pH units is utter bs. It would be 25% more acidic if it moved by 3.5 pH units. True, there are 25% more hydrogen ions, but there are 25% more hydrogen ions for any 0.1 movement in pH. If we used another set of pHs for example, that water at a pH of 7.0 (that is, completely neutral) is 25% more acidic than water at pH 7.1 (barely alkaline) shows you the meaninglessness of their statement.

Micula

The benthic extinction at the PETM is a bit more complex than this study suggests. There was another step in the process of generating the CO2 which is overlooked. The most popular theory of the origin of the CO2 was a massive dissociation of methane hydrate on the continental shelves and perhaps deeper environments. The resultant methane would have quite rapidly (geologically) degraded into CO2. That was not the killer. When one liter of methane hydrate dissociates on the seabed, it produces 160 liters of methane and 800ml of pure water. Note that – pure water – not salt water. The result would have been a fresh water, or at least brackish water horizon at the seabed sediment/ seawater interface. This would have killed or severely depleted benthic faunas. The evidence of this can be seen in some areas where Paleocene/Eocene boundary sediments have manganese layers in sediments interpreted to have been deposited in relatively shallow waters – not the deep waters where manganese nodules are well known to be deposited. Manganese will only precipitate out of sea water in the presence of freshwater. The manganese rich layer at the P/E boundary across the North Sea, for instance, could not have been deposited due to fluvial influences around the basin as it is so widespread. It had to have been a synchronous major event such as a methane dissociation event.
A secondary effect of the release of methane into the oceans at that time would have been a reduction of buoyancy for marine planktic species from whales to foraminifera. The partial extinction of planktic foraminiferal species during the same event may be related to this as some species were more able to cope with the reduction in buoyancy due to their shape than others.
To say that CO2 was the killer is to simplify the extinction event and to focus the attention on a fashionable possibility.
It may be worth saying that the greenhouse earth that developed after this event was responsible for massive greening of the Eocene world which allowed the development of a variety of mammalian species and the rapid evolution of primates.

Any article that claims a pH of 8.1 is acidic is pure BS and it, together with the researchers, should be binned and banned.

johnmarshall

Ocean pH has not been measured for long enough yet to make any assumptions about pH cycles. It has been known for years, longer than the CAGW crap, that ocean pH varies round the planet from 8.4 to 7.6 in surface waters. Waters surrounding thermal vents is acidic at pH4,5 or less.
This claim is total crap produced by morons.

Alex

‘From seafloor sediments drilled off Japan’. There is, off course, no tectonic activity there.
Timothy Bralower, a researcher at Penn State who was not involved in the study. “It took tens of thousands of years to recover.
I guess I can make a legitimate comment too. After all, I wasn’t involved in the study either.
My comment is ‘ Utter BS’

urederra

So, what was the pH of the ocean during the geological epochs when atmospheric CO2 levels were over 1500 ppm?
What is the error in the measurement of pH levels?

Phil

IMHO, there isn’t enough data to reliably calculate the average pH of today’s oceans, let alone the average pH 150 years ago.

tty

Usually I don’t agree with with those who simply dismiss papers as ”garbage” but in this case I tend to agree.
Some 56 million years ago, a massive pulse of carbon dioxide into the atmosphere sent global temperatures soaring.
Actually the best profiles show the normal pattern – warming (and the biotic changes it caused) came first, the carbon isotope changes followed slightly later.
In the last 150 years or so, the pH of the oceans has dropped substantially, from 8.2 to 8.1
The pH scale wasn’t even invented until 1909, and consistently measuring pH differences of 0,1 units in the laboratory is challenging even today, so how do they know?
“ocean acidity increased by about 100 percent in a few thousand years”
And exactly what does 100% mean on a logarithmic scale?
“Up to half of the tiny animals that live in mud on the seafloor—benthic foraminifera—died out during the PETM, possibly along with life further up the food chain.”
One of the most embarrassing things with the PETM is that despite the very large and sudden warming practically no extinctions resulted. About the only exception is the benthic foraminifera (which by the way are very far from the only animals “that live in mud on the seafloor”). That extinction is usually ascribed to the fact that the temperature of the deep seas increased by about 10 degrees (centigrade) in just a few thousand years. There is no sign of any extinctions “further up the food chain”, nor in surface waters where this “terrible acidification” occurred.
To the contrary during the PETM life both on land and in the oceans flourished and dispersed as never since. The ancestors of a very large proportion of the animals alive today (including us) first show up during the PETM.
“more than half of the tiny planktic snails, or pteropods, that she and her team studied off the coast of Washington, Oregon and California showed badly dissolved shells. Ocean acidification has been linked to the widespread death of baby oysters off Washington and Oregon since 2005”
It should be pointed out that the “acidification” in this case is due to increased upwelling of deep water in the coastal areas. Deep ocean water contains less oxygen and more CO2 than surface water. Deep ocean water has a turnover time of c. 1000 years before it returns to the surface. During these 1000 years deep ocean life consumes a lot of the oxygen and turns it into CO2. Upwelling waters incidentally are also very rich in nutrients, so the fisheries on the West Coast are very dependent on these periodic upwellings, though it can be bad for oyster larvae. So – no this “acidification” has little or nothing to do with the modern increase of atmospheric CO2. Must be due to all those medieval SUV:s which caused the MWP.

kadaka (KD Knoebel)

From 2012, a WUWT repost of a great Jo Nova piece examining a new Scripps paper:

Scripps blockbuster: Ocean acidification happens all the time — naturally

It turns out that far from being a stable pH, spots all over the world are constantly changing. One spot in the ocean varied by an astonishing 1.4 pH units regularly. All our human emissions are projected by models to change the world’s oceans by about 0.3 pH units over the next 90 years, and that’s referred to as “catastrophic”, yet we now know that fish and some calcifying critters adapt naturally to changes far larger than that every year, sometimes in just a month, and in extreme cases, in just a day.

This paper is such a game changer, they talk about rewriting the null hypothesis:

“This natural variability has prompted the suggestion that “an appropriate null hypothesis may be, until evidence is obtained to the contrary, that major biogeochemical processes in the oceans other than calcification will not be fundamentally different under future higher CO2/lower pH conditions””


[quoting a Matt Ridley article]

The central concern is that lower pH will make it harder for corals, clams and other “calcifier” creatures to make calcium carbonate skeletons and shells. Yet this concern also may be overstated. Off Papua New Guinea and the Italian island of Ischia, where natural carbon-dioxide bubbles from volcanic vents make the sea less alkaline, and off the Yucatan, where underwater springs make seawater actually acidic, studies have shown that at least some kinds of calcifiers still thrive—at least as far down as pH 7.8.
In a recent experiment in the Mediterranean, reported in Nature Climate Change, corals and mollusks were transplanted to lower pH sites, where they proved “able to calcify and grow at even faster than normal rates when exposed to the high [carbon-dioxide] levels projected for the next 300 years.” In any case, freshwater mussels thrive in Scottish rivers, where the pH is as low as five.

Many additional “acidification” links at Jo Nova, the WUWT version includes the full Matt Ridley piece. Both have informative graphs. Enjoy.

urederra

For those who are wondering:
pH=8.2 gives a H concentration of 6.3095E-9
pH=8.1 gives a H concentration of 7.9432E-9
7.9432-6.3095=1.6337
(1.6337 · 100)/6.3096 = 25.89%

Dave N

So, let me see if I have this straight: human related emissions are adding CO2 to the atmosphere, resulting in warming. (Apparently Mosher says CO2 is a “control knob”, right?).
Warming causes the oceans to warm; when they do, they outgas CO2, correct?
How then do the oceans manage to absorb more CO2, resulting in a lowering of pH? (doesn’t matter whether anyone calls it acidifying, or being less alkaline: that’s what it comes down to).
Are the oceans capable of absorbing more CO2 than they outgas as they warm, because of higher concentrations in the atmosphere? Has anyone proven this using experiments?

Pete Brown

This is a bit bizarre. Ocean ‘acidification’ is if anything causing the ocean to become less alkaline based on those pH values – as others have commented. But we have to assume surely that the authors of this work also know this. So what would they say is the reason why the ocean becoming more neutral is bad for shellfish? I’d they were here defending their work I mean? We can’t just assume they don’t know basic chemistry surely?

Twobob

Caustic comment about acidic sea.
Fish swim and pee in the sea.
Bull Mer’d comes from land.

Siberian_husky

Thankyou Urederra- the first intelligent comment on this thread.

Alex

Siberian_husky says:
June 4, 2014 at 2:06 am
Thankyou Urederra- the first intelligent comment on this thread.
Wow! Really?

kadaka (KD Knoebel)

Siberian_husky said on June 4, 2014 at 2:06 am:

Thankyou Urederra- the first intelligent comment on this thread.

Thanks for the insult. The best to you too, bud.
So which of the two urederra comments was the first intelligent one? If it was the second, in what ways were the first one unintelligent? If the first, does the second also pass your threshold for Sign of Intelligence?
Offhand I’d think someone bright enough to absolutely determine which was the first intelligent comment, would have been smart enough to say which comment that was. But that could just be me.

Dave N

Alex:
“Siberian_husky says:
June 4, 2014 at 2:06 am
Thankyou Urederra- the first intelligent comment on this thread.
Wow! Really?”
If you were thinking SH was referring to Urederra’s explanation of the 25% change, I expect it may actually have been Urederra’s first comment, regarding pH levels in other epochs; like in the Cambrian, for example, when corals evolved.

knr

Acidification a nicely scary sounding word
Less alkene , boring sounding but more accurate word s.
You decide which one you will use when you’re looking for funding .
Meanwhile once again using ‘proxies ‘ we are told how things can be ‘measured ‘ from millions of years ago and they ‘compared’ with actual valid measurements from observations now , BS of the first order .

Alex

Dave
which one of those two is worthy of the Nobel Prize?
I’m not saying there is anything wrong with those comments. I’m just wondering why those 2 comments are considered ‘the first intelligent’. I saw many other comments that were intelligent too. I’m getting the feeling that there are ‘sock-puppets on this thread.
urederra says:
June 4, 2014 at 1:24 am
So, what was the pH of the ocean during the geological epochs when atmospheric CO2 levels were over 1500 ppm?
What is the error in the measurement of pH levels?
2nd comment
urederra says:
June 4, 2014 at 1:46 am
For those who are wondering:
pH=8.2 gives a H concentration of 6.3095E-9
pH=8.1 gives a H concentration of 7.9432E-9
7.9432-6.3095=1.6337
(1.6337 · 100)/6.3096 = 25.89%

David Schofield says: June 4, 2014 at 1:10 am
“Seriously. Can someone explain to me how the warming oceans take up this carbon dioxide whilst at the same time giving it off??”

CO2 flux goes both ways. And there’s a seasonal movement – loss during summer, gain during winter.
On balance, more CO2 goes into the sea if the CO2 ppmv in air rises; less if the sea is warmer. Since CO2 in air has risen, and the sea has warmed, these effects compete. So far, higher CO2 ppmv has prevailed, and the sea has absorbed CO2, but your link says, for the reasons given, this may change.
Jeff Szuhay says: June 4, 2014 at 12:34 am
“A pH of 7.8… Uh, that’s still alkaline. Not acid until it goes below 7.0.”

pH 7 is the neutral point of pure water. Marine organisms never encounter pure water, so that is irrelevant. They have evolved in a sea of pH>8.
Human blood has a pH of about 7.4. If it drops to 7.35, that is acidosis = bad news. Blood pH 7 is not compatible with life.

Alex

Nick
‘Since CO2 in air has risen, and the sea has warmed, these effects compete. So far, higher CO2 ppmv has prevailed, and the sea has absorbed CO2’
Can you point me towards some literature that can verify the last sentence?

observa

This sort of stuff just has to stop as it’s all most unsettling for earth scientists-
http://blogs.news.com.au/dailytelegraph/timblair/index.php/dailytelegraph/comments/fault_lines/

michael hart

Trenberth cannot even measure the temperature of the world ocean. What makes these people think they can measure the pH any more accurately?
There are also reasons to think increased CO2 will be beneficial:
https://www.researchgate.net/publication/229561219_ELEVATED_ATMOSPHERIC_CARBON_DIOXIDE_INCREASES_ORGANIC_CARBON_FIXATION_BY_EMILIANIA_HUXLEYI_%28HAPTOPHYTA%29_UNDER_NUTRIENTLIMITED_HIGHLIGHT_CONDITIONS1
The exoskeleton also grows thicker. Another study looked at genetic changes under elevated CO2 and found only decreased carbonic anhydrase expression. Again this suggests life becomes easier.

hunter

The physical evidence for the pH change is lacking. This study also does not offer any explanation why we should be worried about this derived alleged 0.1 reduction in pH in a system whose dynamic range is in reality much, much wider. Additionally, they offer no evidence that ocean absorption goes simply to physical chemistry of seawater and not to biological and geological processes.
Once again we see a marketing effort by the CO2 obsessed dressed up as science.

Alex says: June 4, 2014 at 3:00 am
“Can you point me towards some literature that can verify the last sentence?”
Yes. AR4 7.3.1 describes the carbon cycle. It gives many references. Key quote:
“Thus, the terrestrial biosphere and the oceans together have consistently removed 45% of fossil CO2 for the last 45 years, and the recent higher rate of atmospheric CO2 increase largely reflects increased fossil fuel emissions.”
michael hart says: June 4, 2014 at 3:05 am
“Trenberth cannot even measure the temperature of the world ocean. What makes these people think they can measure the pH any more accurately?”

pH is determined by equilibrium relations involving carbonates, which are much more abundant in the sea than H+ or CO2. Two quantities, dissolved inorganic carbon (DIC) and total alkalinity, are easy to measure, are fairly stable, and pH can be deduced when you know them.

son of mulder

What I don’t understand is why during the last iceage (and previous ones) the ocean pH was just under 8.25, because then I assume the ocean was colder so would hold more CO2 per unit volume and hence make pH lower than the interglacial pH of 8.15, well before any anthropogenic influence. Similarly when sea-ice forms then CO2 is expelled so would tend to decrease pH as it is absorbed into the cooling ocean. see
http://www.nature.com/scitable/knowledge/library/ocean-acidification-25822734
http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0889.2011.00571.x/abstract
I could imagine if the carbon cycle slowed significantly then chemical action with rocks could become the predominant factor in reducing disolved CO2, and hence increasing pH. Is this the explaination?

About CO2 uptake and release by the oceans:
– seawater in equilibrium with the atmosphere gives 17 ppmv higher levels for each 1°C increase in temperature. See:
http://www.ldeo.columbia.edu/res/pi/CO2/carbondioxide/text/LMG06_8_data_report.doc
That is a dynamic equilibrium: some 50 GtC as CO2 goes in and out the oceans over the seasons (mainly in the mid-latitudes) and some 40 GtC/year is released at the upwelling places near the equator (mainly off the coast of Chili) and taken away near the poles (mainly NE Atlantic). A temperature increase augments the releases and depresses the uptakes, which leads to an increase in the atmosphere, until the new equilibrium is reached:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/upwelling_temp.jpg
– humans have emitted some 370 GtC over the past 160 years. The atmospheric increase is over 200 GtC (100+ ppmv).
An increase of 1°C since the LIA is responsible for maximum 17 ppmv (ocean only) or historically 8 ppmv (ocean + land vegetation), far from the measured 100+ ppmv increase.
Humans currently emit ~9 GtC/year (4.5 ppmv/year). The extra pressure caused by 100+ ppmv CO2 above equilibrium (for the current temperature around 290 ppmv) gives a net sink of ~4.5 GtC/year of which ~1 GtC/year in land vegetation, ~0.5 GtC/year in the ocean surface layer and the rest of ~3 GtC/year in the deep oceans. Other possible sinks are either too small or too slow…

Alex

Nick
Thanks for that link, but unfortunately I consider IPCC information as suspect. I will fall back on my high school science.
I learned that solids dissolve in liquids and the amount of solid dissolved in said liquid was temperature dependent. Excess solid would not dissolve. I am excluding super saturation because that requires special conditions.
With gasses in fluids it is a reverse effect. That is, higher temperatures lower the solubility of gasses. The effect is temperature dependent and not dependent on availability/excess gas. In other words if you had 5000 ppm CO2 in the air it would not dissolve more CO2 into water unless you changed the temperature of the water. In actuality the water would have to be colder to absorb more gas.
So I guess I am saying that with higher sea temperatures you would have less dissolved CO2 and therefore higher pH. With colder seas you would have more dissolved CO2 and a lower pH. It makes no difference how much CO2 is in the atmosphere because solubility is temperature dependent

rogerknights

The problem with the “25% more acidic” statement is that it implies that acidification has progressed 25% of the way to neutrality, which isn’t so.

Alan the Brit

We have an expression here in Blighty for such a study, & this one sounds absolute “bollocks”! Apologies, bad hair day!

Donald Mitchell

Please provide citations to non paywalled studies which include raw data that indicate our capability to estimate (i say estimate since only a fool would believe that we could actually measure it) the distribution of pH throughout the volume of the oceans. I would be very curious to see just what the spatial and temporal sampling of the data is along with reasons to believe that there is enough data to justify the estimated probable error bands. Would one sample from each thousand cubic miles be enough? If it would, you would only need a little over 320,000 samples to get spatial coverage. What about temporal coverage? How could you demonstrate that such sampling was adequate? My only experience in this area is running a plating shop where we had to control acid based plating baths. The biggest one was 1.3 cubic meters and we did not need to control it as close as 0.1 pH units but, after sitting overnight, it had to be thoroughly mixed before we could get a valid sample.
It would take quite a project to convince me that you could estimate the pH of San Francisco Bay to within 0.1 pH units. Then you would need to show that combining all of that data into one number was meaningful.

Alex says: June 4, 2014 at 3:54 am
“The effect is temperature dependent and not dependent on availability/excess gas. In other words if you had 5000 ppm CO2 in the air it would not dissolve more CO2 into water unless you changed the temperature of the water.”

No, that’s not true. Henry’s Law says that the amount dissolved is proportional to ppm. The constant depends on temperature.
Upthread, Ferdinand has said that ppmv CO2 in equilibrium with seawater rises about 17 for each °C rise in SST. That means that warming so far might raise ppmv CO2 by about 12. But our fossil fuel burning has raised air CO2 by about 120 ppmv. That dwarfs the warming effect and forces CO2 into the sea.

Leonard Weinstein

Nick Stokes Says:
Nick, comments of others asked how the average ocean pH was measured to an accuracy of 0.1 over 100 years ago, and how the global ocean average is known when only small parts of the worlds oceans are (and were) even measured. Both these issues make the claims absurd. Also it was pointed out that in the PETM, it appears the rising temperature preceded the Carbon pulse, which then caused a temperature spike. It appears there was a warming trend (at a level much warmer than present) that eventually resulted in a methane release at some point in the warming trend. Even after recovery from the effect of the Carbon induced pulse, the average temperature still continued to climb, to a level comparable to the peak of the pulse spike. It does not appear that you or I know what was going on, but it is fairly clear that Carbon is the main control knob is too simplistic. Yes is has an effect, and can cause heating, but other effects do also, and the sensitivity cannot be determined from the PETM data.

A good pH meter has .01pH accuracy. About 10X the noted change. So if it was done by measurement the numbers are valid +/-20% of the change. That is also dependent on calibration. Accuracy of temperature measurement. And possible confounding factors.

JK

Alex wrote:
‘Thanks for that link, but unfortunately I consider IPCC information as suspect. I will fall back on my high school science. … With gasses in fluids it is a reverse effect. That is, higher temperatures lower the solubility of gasses. The effect is temperature dependent and not dependent on availability/excess gas. In other words if you had 5000 ppm CO2 in the air it would not dissolve more CO2 into water unless you changed the temperature of the water.’
Surely you studied Henry’s Law? Quoting wikipedia:
“At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.”
(http://en.wikipedia.org/wiki/Henry's_law – you can also find this on various school chemistry revision websites. Also e.g. Lubos Motl, a climate skeptic quotes the same definition – I don’t want to clutter this comment with too many links.)
Maybe I have this wrong. If so I would appreciate a link to an explanation.

kadaka (KD Knoebel)

From Nick Stokes on June 4, 2014 at 3:21 am:

michael hart says: June 4, 2014 at 3:05 am
“Trenberth cannot even measure the temperature of the world ocean. What makes these people think they can measure the pH any more accurately?”

pH is determined by equilibrium relations involving carbonates, which are much more abundant in the sea than H+ or CO2. Two quantities, dissolved inorganic carbon (DIC) and total alkalinity, are easy to measure, are fairly stable, and pH can be deduced when you know them.

pH has been accurately measured for quite some time now, using common laboratory things like precision litmus papers. But electronic pH meters are normally used. They need frequent calibration against reference solutions, for best accuracy you calibrate before every measurement. Don’t expect more than two decimal places of precision.
Out of the lab, there are pH meters suitable for processing equipment in industrial uses, where calibration is much less frequent, as well as inexpensive “home use” models for aquariums and hydroponics (example), +/-0.1 accuracy.
Where they are measuring, they can measure pH reasonably accurate with field-grade equipment.
But as with temperature, the issue is spatial coverage of the measurements. You don’t measure the pH of an ocean at one spot. Nor at twenty. You’ll need a heck of a lot more measurements, and we don’t have them, nor do we have long records of sufficient many measurements thus we lack temporal coverage for calculating changes and trends.
BTW, if anyone knows what Nick is chattering about and how that relates to measuring by simply sticking a probe into seawater, feel free to elucidate.

Eugene WR Gallun

From my poem — Al Gore American Bloviator
If acid rain scared you think about this!
Oceans acidic and warmer than piss!
Eugene WR Gallun

Leonard Weinstein says: June 4, 2014 at 4:30 am
“how the average ocean pH was measured to an accuracy of 0.1 over 100 years ago”

Measurement would be no problem. As I said above, all that is needed is DIC and TA. DIC is gravimetric (precip with BaCl2) and TA is just titration (methyl orange). To get pH to .1, that conventional chemistry has to be 25% accurate.
As to how widely this was done, I don’t know.
“it is fairly clear that Carbon is the main control knob is too simplistic”
Yes, but who says it is? This paper says that one particular CO2 pulse caused warming. But they don’t say all warming is caused by CO2, and few do. In fact events forcing CO2 higher, causing subsequent warming are not common. This methane pulse (if so) may have been one, and our mining fossil fuel is another.

John West

” more than half of the tiny planktic snails, or pteropods, that she and her team studied off the coast of Washington, Oregon and California showed badly dissolved shells.”
I’d like to know how a supersaturated solution such as surface seawater can dissolve shells. A decrease in pH merely decreases the amount of calcium carbonate (and alkalinity in general) that can be kept in solution without precipitation.