Rate May Be Ten Times Faster, According to New Data
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.
When earning my chemistry degree, a failure to do proper error analysis and report it with your results would have resulted in a “D”. Show me the error analysis and how the resulting uncertainty in all the measurements (for past and current pH claims) does not invalidate all your conclusions.
I have waited in vain for an advocate of Global Lukewarming to publish research on the ideal climate so we can know if ours is trending towards or away from that metric. But alas, I can only find information about the interglacial period. Nobody seems interested in knowing the ideal. Why might that be? Maybe because there is no juice in that research.
Likewise, what is the ideal pH of the ocean?
“Men whose research is based on shared paradigms are committed to the same rules and standards for scientific practice. That commitment and the apparent consensus it produces are prerequisites for normal science, i.e., for the genesis and continuation of a particular research tradition.” — Thomas Kuhn.
rgbatduke says:
June 4, 2014 at 5:14 am
. It might well cause “catastrophic” changes in ocean chemistry.
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Then ask yourself how is it possible to keep fish aquariums in closed houses and buildings..where CO2 levels can exceed 1000ppm….
The oceans can not change pH until they run out of buffer…
..if you think CO2 will change the pH of the oceans…you have to first believe the oceans will run out of buffer
Atmospheric CO2 levels are nothing compared to biological processes…..Biology in the oceans is producing magnitudes more acidic compounds right now…..it will laugh at higher CO2 levels…and it’s the biology that’s buffering the oceans
One good to come out of pointing out the many holes in this latest bit alarmist propaganda is an opportunity to review carbon sinks.
One very important carbon sink is that of the freshwater systems of the world.
Although tiny in relation to oceans, freshwater systems are huge in the carbon cycle. And humans have created lakes and resevoirs worldwide. Limnology is the science that studies this, and a review of the implications of how powerful a role the freshwater systems of Earth play in the carbon cycle is eye opening.
tty – well said regarding the upwelling CO2-rich deep waters on the West coast.
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From the article:
” Eventually, the oceans and atmosphere recovered as elements from eroded rocks washed into the sea and neutralized the acid.”
If it remained alkaline all the time how can they speak of ‘the acid’ being ‘neutralized’? That is pretty poor chemistry, if you ask me. The article makes hay out of common misunderstandings about hydrogen ions in water. It got published, but should be binned. It does not add to understanding. It rather profits from exploiting common misunderstandings.
Looks like a blip, not a spike, of CO2 on a descending slope had no effect on temperatures. Obviously the Aragonia velascoensis went extinct because the CO2 was too low, much lower than when it evolved.
http://i46.tinypic.com/2582sg6.jpg
From John Eggert on June 4, 2014 at 5:58 am:
I know, and I noticed there are nice equations for calculating them using pH. Which is easily read off a meter.
Which was the issue. There was a simple question about measuring a quantity with accuracy, and Nicky wanted to show off by whipping out his big shiny throbbing intellect instead, with a complicated response about easily (for a chem major) deducing it.
Someone wanted to know about measuring temperature, Nicky talked about easily calculating it from relative humidity and the maximum air speed of a Northwest-flying English sparrow.
Why he keeps harping on some obsolete method kept around as an academic exercise when the modern faster way is long established, well, maybe he just likes telling passerby about his favored elaborate routine for keeping his intellect stimulated.
For any journalists in here. I think the story to be told is the story of those that believe in catastrophe and doom against those holding with the Gaia hypothesis. Gaia posits that organisms interact with their inorganic surroundings on Earth to form a self-regulating, complex system protected from the ravages of a runaway greenhouse effect. On the one hand Gaia is a more complex description and doesn’t jibe with Occam’s razor that the simpler explanation is the better one. On the other hand, in general, there is nothing simple about Earth Systems, and models diverging from actual surface temperatures are probably in need of more factors and more complexity.
I rather thought that, in a basic buffered solution, adding carbonic acid depleted carbonate by forming bi-carbonate without an increase in hydronium ions and a concomitant lowering of pH.
People want to think that earth systems are as simple and bound in universality as the general laws of physics. In truth there is little appreciation of how complicated this brand of science is. The science can’t be settled because there’s still too much territory to be explored.
Rubbish.
mebbe “basic buffered solution” is that “basic” as in non-acidic?
catweazle……not to say laws of physics don’t apply. Just that analysis of earth systems is not a simple matter that can be carried out the way that things are done in a controlled laboratory environment.
Ferdinand Engelbeen says:
“Anyway, if the mass extinction was caused by more CO2 or a lower pH, remains questionable, as a lot of other variables changed too.”
It is not often one finds factual errors in FE:s posts, but the odd thing about the PETM was that there wasn’t any mass extinction.¨
Also it is by no means certain that the changes in carbon isotope ratios at the PETM was due to release of methane hydrates. At least seven alternative hypotheses have been suggested:
1. Massive peat fires (the total absence of any large terrestrial plant-eaters after the extinction of the dinosaurs would have facilitated accumulation of plant material)
2. Oxidation of organic bottom sediments desiccated by tectonic movements related to the opening of the North Atlantic.
3. Baking out of buried organics by the massive basalt eruptions related to the opening of the North Atlantic
4. Melting of large areas of permafrost in the interior of Antarctica
5. Cometary impact
6. Massive outgassing of CO2 from the oceans due to warming of oceanic bottom water.
7. Methane hydrate dissolution.
None of these is obviously absurd or impossible, and of course any combination of two or more mechanisms is also possible.
They use the problems that shell fish farms off the coast of Washington State are having as an example of the effects of change in pH, but there may be another mechanism in play.
Victoria BC is still dumping the equivalent of a supertanker full of raw sewage into the Puget Sound each week. 130 million liters per day. There are two sub-surface outfalls in the Strait of Juan de Fuca, across from Port Angeles. Because they are out of sight, not many know about it.
The decay of “organic material” in water acts to consume dissolved oxygen. Reducing dissolved oxygen also has the effect of reducing pH. The chemicals that are put down the drain, such as soaps, detergents, etc, and heavy metals also combine with dissolved oxygen and reduce pH.
I am aware of local divers giving anecdotal evidence of this as they have observed deeper dwelling creatures struggling to get enough oxygen. The diffusion rate of oxygen at deeper levels is much slower – it takes a while for surface oxygen to get down there, especially without mixing.
This water is drawn into the Puget Sound by tidal action, where is is concentrated, then back out again and driven down the coast by prevailing currents. This is why reports of acidification are so localized – in this case Washington and Oregon coastline. If CO2 levels were responsible for ocean acidification on the scale they are stating, it would be widespread, as CO2 levels do not vary much with map coordinates. But that is not the case.
Also, what about the period in earths history when CO2 levels were at least two times higher than they are now? What was ocean pH back then? Weren’t the shellfish in question establishing their place on the planet at that time? IF what they say is true, then pH must have been much lower, yet those shellfish are here today.
Alex says:
June 4, 2014 at 6:06 am
You can’t be serious about referring to Henry’s Law, which specifically refers to constant temperature. The changes in partial pressure of CO2 these days are laughable when you try to calculate the solubility of CO2 in water by using Henry’s law. An extra CO2 molecule dissolved in a litre of water is insignificant to the pH. The greatest effect is in the temperature.
Don’t take my word for it. Refer to data that shows that CO2 in the atmosphere increases after temperature rise
Yes it was serious and correct to refer to Henry’s law, unfortunately you continue to reveal your ignorance on the subject! The Henry’s Law ‘constant’ is usually defined at 298K, however the more accepted usage is the HL ‘coefficient’ which reflects the fact that it is a function of temperature. Typically for CO2 in seawater the equilibrium partial pressure will double with a 16K increase in temperature. The pCO2 has increased by ~25% since 1960, far more than the rise in SST necessary to cause such an increase.
HankHenry says:
June 4, 2014 at 7:22 am
mebbe “basic buffered solution” is that “basic” as in non-acidic?
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Yes. AFAIK, bicarbonate is amphoteric, taking H from carbonic acid and giving H to carbonate
The decay of “organic material” in water acts to consume dissolved oxygen.
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Kurt, that’s a biological problem…..aerobic/suboxic bacteria consume the oxygen, and produce magnitudes of acid….it’s the bacteria reducing the pH
You’re right, CO2 has nothing to do with it
tty, you are right. Besides the benthic foraminifera, there was no mass extinction and lots of possible causes for the PETM.
Nick
Why do you have yourself, on your website, as a ‘Scientist’? I have only encountered ‘scientists’ in Science Fiction novels. You seem to have considerable knowledge in the climate sphere. I probably could be like you with documents and graphs that I could ‘cut and paste ‘ from too.
Unfortunately there is a big difference between having knowledge and having the ability to use it
mebbe says:
June 4, 2014 at 7:14 am
I rather thought that, in a basic buffered solution, adding carbonic acid depleted carbonate by forming bi-carbonate without an increase in hydronium ions and a concomitant lowering of pH.
I’m afraid not.
CO2 (aq) + H2O ⇆ H2CO3 ⇆ HCO3− + H+ ⇆ CO32− + 2 H+
See the associated Bjerrum plot:
http://www.nature.com/scitable/content/ne0000/ne0000/ne0000/ne0000/25853439/2-626w_1_2.jpg
hunter says:
June 4, 2014 at 7:01 am
One very important carbon sink is that of the freshwater systems of the world.
Although tiny in relation to oceans, freshwater systems are huge in the carbon cycle.
Fresh water dissolves very little CO2, because it has no buffer capacity at all and therefore is slightly acidic. That does dissolve carbonate rocks, but even that costs a lot of time to digg out the beautifull underground caves…
I think there is an elephant in the room that is not being accounted for.
First, let’s do a simple, sober game-developer’s top-down analysis:
We are adding ~3 BMTC per year to an ocean sink of ~1800 BMTC down to below biota level (and ~42,000 BMTC below that). Some of that is transported downward. ~2 BMTC per year is “lost” to the deep sea floor.
But then there is the elephant.
Acidification has been occurring since 1750, according to the literature. But CO2 did not even begin to increase until 1850, and did not exceed 300 ppm until a century after that. Thus stipulated, this tells me that other factors are in play.
So what might those factors be? Draining, dredging, and dumping spring to mind. Especially as pH increase (as logy as those measurements are) appears to have occurred primarily in and near the coastal areas. There is not only the direct acidifying effect of the decaying effluence, but also the fact that a a large chunk is converted by biota into carbonic acid, much the same as CO2.
That would account for the 1750 start date. What we need to do is quantify those non-CO2 effects — dumping, draining, dredging (and whatever other factors may or may not apply) — and determine how much of a relative impact they have on carbonic acid and H+ levels, and see how it adds up and compares with what we (sort of) know. What are those impacts? Quien sabe? But I’m willing to bet heavily they are not zero.
Any attempt at quantification will be complicated by the wildly varying local pH and the fact that it is, so far, poorly measured. But I think that is what we need to do is conduct studies on non-CO2 anthropogenic feed-ins to the biological mechanisms that produce carbonic acid.
Then we may actually begin to get a handle on all this.
Nick, even though most of us disagree with what you say at least you do it constructively. Keep it up. It’s good to get a different perspective.