Taking things with a grain of salt
One of The Git’s friends is very much enamoured of Thermageddon, but refuses to discuss the issue on the grounds that The Git knows far more about climate than he does. He has however made alarmist claims where his expertise exceeds The Git’s. To boot, he is a marine biologist, and that’s an area of biology that The Git had not studied at all closely until quite recently. The specific claim made by alarmist marine biologists is, to quote the Wiki-bloody-pedia, “there is evidence of ongoing ocean acidification caused by carbon [dioxide] emissions”. According to the Oxford English Dictionary (and several other authoritative dictionaries), acidification means to make acidic. Chemists, marine or otherwise, measure acidity and alkalinity on what is called the pH scale where 7 is neutral, greater than 7 is basic (alkaline) and less than 7 is acidic.
Contrary to alarmist marine biologists’ claims that the oceans are becoming increasingly acidic, the oceans are decidedly alkaline varying between ~pH 8 and pH 9. So, where does this claim that anthropogenic carbon [dioxide] emissions have made the oceans acidic (the pH to fall below pH7) come from?
According to Mark Z. Jacobson, whose paper Studying ocean acidification with conservative, stable numerical schemes for non equilibrium air-ocean exchange and ocean equilibrium chemistry appeared in the Journal of Geophysical Research, “surface ocean pH is estimated to have dropped from near 8.25 to near 8.14 between 1751 and 2004, it is forecasted to decrease to near 7.85 in 2100 under the SRES A1B emission scenario, for a factor of 2.5 increase in H+ in 2100 relative to 1751.” Note the dates and the accuracy of the pH to two decimal places. Also note that the pH values are not less than 7; the oceans are basic!
The measurement of relative acidity and alkalinity using pH was introduced by Danish chemist Søren Peder Lauritz Sørensen at the Carlsberg Laboratory in 1909. The scale was later revised to the modern pH in 1924 to accommodate definitions and measurements in terms of electrochemical cells. Thus the pH of anything as variable as seawater prior to 1909 cannot be known by definition!
It gets worse. Measuring the pH of strongly ionic solutions such as seawater is difficult and techniques to deal with accurate estimates of seawater pH weren’t developed until the 1980s and 1990s. There are three main methods in use and the results they give do not agree with each other; they vary by as much as the purported pH change. The introduction of a reasonably inexpensive and sufficiently accurate technique using the Honeywell DuraFET pH sensor was only developed over the last ~15 years. So, the claimed decrease in ocean pH over more than 250 years is based at best on 30 years of actual data; more likely 15 years.
The alarmist marine biologists making these claims are trading on the general public’s ignorance of the well-accepted definition of what is acidic and what is alkaline (basic). They are also trading on ignorance within the general scientific community of the difficulties involved in measuring seawater pH.
Because of a variety of problems inherent in electrometric pH measurements, including electrode drift, electromagnetic interference and problems with the reference electrode, the precision of these pH measurements is relatively poor. On average, we obtain a precision of +0.02 pH units on replicate samples. The accuracy of our pH measurements are difficult to evaluate directly because we have no seawater standard for pH measurements. The accuracy is therefore dependent primarily on the accuracy of the seawater buffers that are used for electrode calibration. In order to improve the precision of our time-series pH measurement data, we are currently evaluating the spectrophotometric methods for pH measurements described by Byrne et al. (198_). Although these measurements are currently being made on a regular basis, the methodological details are not finalized and are not described here. [Emphasis The Git’s]
The pH change over 250 years is claimed to be 0.11. The following diagram shows the pH changes on a daily and seasonal basis in what RA Horne’s Marine Chemistry (1969) calls a “shallow Texas bay”. In summertime, the pH is ~8.2 at 6 am and 8.9 at 6 pm, a not much less range than is claimed for the 250 year period. Similarly, the pH at 6 pm in winter is 8.4 or lower by 0.5 than in summertime.
There is a multitude of problems facing the would-be measurer of seawater pH. If you measure the pH of the sample in the dark, the result is different than if the lights are turned on. Filtering the seawater to remove living and dead organic matter alters the pH as does changing the temperature. Pure water is pH 7.0 at 25°C and 6.55 at 50°C. Seawater pH falls rapidly with increasing depth near the surface. Taking these factors into account as well as the varied techniques in use, it would appear to be an impossible task to gather sufficient real-world data to make an estimate of pH change over decades, let alone the centuries of the claimed change. There would appear to be no standardised method for reconciling the differences inherent in measuring seawater pH. It seems to be computer models substituting for real data (again).
Putting all that aside, the real interest here is the purported effect of pH change on marine organisms.
Emphasis in the quotes are The Git’s
Oceana [sic] acidification may cause many negative effects on a variety of marine species and ecosystems, which would have rippling consequences throughout the entire ocean. One of the most devastating impacts of rising ocean acidity could be the collapse of food webs.
Marine animals interact in complex food webs that may be disrupted by ocean acidification due to losses in key species that will have trouble creating calcium carbonate shells in acidified waters. Some species of calcifying plankton that are threatened by ocean acidification form the base of marine food chains and are important sources of prey to many larger organisms.
Note the repeated use of the weasel-words in this scare-literature: may, could, are expected as well as the continual use of the word acid to refer to seawater that is nowhere acidic, but everywhere alkaline. Experiments conducted to demonstrate shell-loss appear to use hydrochloric acid (HCl) to decrease the pH of seawater, rather than the demon carbon [dioxide]. While HCl reliably alters seawater pH, carbon [dioxide] participates in a process known as buffering when it dissociates into carbonate and bicarbonate ions in seawater. Buffered solutions resist pH change.
Here, Jennifer Marohasy shows a couple of photographs of “active underwater fumaroles pumping out virtually pure CO2. The sea grass is extraordinarily lush and healthy and there is very healthy coral reef a few metres away.”
Some marine biologists have claimed that these photographs are deceptive in that they show organisms already adapted to the high levels of CO2 around these fumaroles. While this is true, and the adult organisms are sessile, their juvenile stages are not. They are free-swimming and thus also adapted to the conditions in the wider ocean. Clearly they are quite capable of coping with a wide range of conditions, something that would come as no surprise to anyone even vaguely acquainted with Earth’s wide range of temperatures and CO2 levels over past millennia.
Quoting again from Effects of Ocean Acidification on Marine Species & Ecosystems:
Tiny swimming sea snails called pteropods are considered the ‘potato chips of the sea’ as they serve as a critical part of the arctic marine food web, ultimately feeding whales and other top predators. Pteropod shells are expected to dissolve in acidity levels predicted by the end of this century and may not be able to survive. Population crashes or changes in the distribution of pteropods would have serious implications for some of the most abundant marine ecosystems.
Other important calcifying species have been witnessed to have troubles in acidified waters.
Sea urchins are important grazers and can help to protect coral reefs from encroaching algae. Young sea urchins have been observed to grow slower and have thinner, smaller, misshapen protective shells when raised in acidified conditions, like those expected to exist by the year 2100. Slower growth rates and deformed shells may leave urchins more vulnerable to predators and decrease their ability to survive. Furthermore, under acidified conditions the sperm of some sea urchins swim more slowly, this reduces their chances of finding and fertilizing an egg, forming an embryo and developing into sea urchin larvae.
Dr J Floor Anthoni writes:
As far as measuring the effect of raised CO2 levels on marine animals, the situation is complicated because CO2 rapidly becomes toxic, with symptoms of depression of physiological functions, depressed metabolic rate + activity + growth, followed by a collapse in circulation. Remember that free CO2 amounts to only 1% of the total CO2 ‘bonded’ to the water and that it takes some time for equilibrium with the other CO2 species to happen. It is thus too easy to overdose the free CO2 by increasing the CO2 in the air above. In other words, it is nearly impossible to mimic the natural situation truthfully in an experiment. [Emphasis in the original]
All of this reminds me of a made-up scare by marine biologists back in the 1970s. Supposedly, the Crown of Thorns starfish (Acanthaster planci) was going to completely devastate the Great Barrier Reef within a decade or so. Forty years on, no such devastation has occurred, although limited areas of the reef have seen coral denuded by them. It turns out that marine biologists who actually dive in the corraline waters observe the beneficial effects of the Crown of Thorns starfish on coral. Coral reefs in tropical waters are severely damaged by intense cyclones (called hurricanes in the Northern Hemisphere) and the Crown of Thorns starfish perform their good works during the recovery phase. Not all corals grow at the same rate and without the starfish, the faster growing branching corals would predominate over the slower growing corals. The starfish, by preferential feeding on the branching corals enable the slower growing corals to thrive.
Quoting again from Effects of Ocean Acidification on Marine Species & Ecosystems:
Squid are the fastest invertebrates in the oceans and require high levels of oxygen for their high-energy swimming. Increasingly acidic oceans interfere with the acidity of a squid’s blood and consequently the amount of oxygen that it can carry. Squid are important prey for many marine mammals, including beaked and sperm whales. Squid fisheries are also the most lucrative fishery in California accounting for 25 million dollars in revenues in 2008.
This is perhaps the weirdest claim of the lot. Animal blood, like seawater, is highly buffered and individuals’ blood pH has no relationship to the pH of the local environment. Rather it is under the control of the respiratory system. While it’s certainly important for animals to maintain optimum blood pH, no animal, marine or terrestrial that The Git knows of exposes its blood to pH influences external to its skin. The Git knows of women who wash their hair in vinegar (an acid) and those who wash their hair with soap (an alkali). Neither, to the best of his knowledge, suffer from acidosis, or alkalosis as a consequence.
When pressed for explanation for the falsehood that the oceans are acidic, those responsible respond that acidification means lowering pH. Actually, there is no authoritative source for this claim. When pressed for a source, the Thermageddonists as usual cannot quote an authoritative reference. When The Git was studying chemistry in 1969, shifting pH towards the neutral point (7) was called neutralisation, never was it called acidification.