Category: oceans


Watts Up With That is a very, very silly website.

Here’s what I mean: In a recent article at WUWT, chemical engineering graduate Steve Burnette tries to dismiss concerns about ocean acidification, but his claims are outright wrong when they are coherent. The centerpiece of the article is a calculation meant to estimate the change in ocean pH over the 20th century. Unfortunately, it’s been badly bungled.

First, let’s go over a few preliminaries.

The carbon dioxide system

Figure 1: The carbonic acid equilibrium system. Atmospheric CO2 is in equilibrium with dissolved CO2, which in turn is in equilibrium with carbonic acid. The acid has a tendency to lose its hydrogen ions, forming bicarbonate ion, which it is also in equilibrium with. The bicarbonate can also lose a hydrogen ion, forming carbonate. Keep in mind that these steps work in reverse; in particular, carbonate ions can react with hydrogen ions to form bicarbonate.

When fossil fuels are burned, about a third of the resulting carbon dioxide ends up dissolved in the oceans. There, it undergoes a series of reactions, first combining with water to form carbonic acid, then losing protons one at a time. The result is a mixture of dissolved CO2, bicarbonate, and carbonate ions, as well as an increase in hydrogen ions, which increase the acidity of the seawater.

Burnette mentions a few principles which are useful for analyzing this scenario. The equilibration between gaseous CO2 and dissolved CO2 is expressed by Henry’s law, which states that the concentration of dissolved CO2 is proportional to the partial pressure of atmospheric CO2. This means that, as CO2 concentrations increase in the air, they will increase in the oceans too. Mathematically: Continue reading

There is a companion article exploring the issue from the perspective of environmental monitoring over at ArkFab.

Human influence on the environment has increased dramatically over the last 10,000 years, to the point that some geologists have argued that human reworking of the earth defines a new geologic age, The Anthropocene. (Zalasiewicz et al, 2008) Much of the focus has been on relatively robust, tangible changes in biogeochemistry. Examples include:

  • megafaunal extinction, accelerated erosion (Zalasiewicz et al, 2008) and nitrogen fixation resulting from the spread of intensive subsistence patterns
  • the loss of stratospheric ozone resulting from the release of novel chlorofluorocarbons

However, fleeting and less tangible effects are also important. Two examples are:

  • the light pollution resulting from urbanization and transportation infrastructure
  • changes in the acoustic environment resulting from direct addition of sonic energy and memes, as well as indirect sources.

A year-long composite view of the earth at night, showing human light generation. White lights are cities; blue lights are fishing boats; green lights are natural gas flares, and red lights are ‘ephemeral light sources’, interpreted as fires. Image from  NOAA National Geophysical Data Center – click for source + discussion.

Light pollution, the scourge of urban astronomers, is a well-accepted phenomenon with serious consequences. A 2004 review begins:

In the past century, the extent and intensity of artificial night lighting has increased such that it has substantial effects on the biology and ecology of species in the wild. We distinguish “astronomical light pollution”, which obscures the view of the night sky, from “ecological light pollution”, which alters natural light regimes in terrestrial and aquatic ecosystems. Some of the catastrophic consequences of light for certain taxonomic groups are well known, such as the deaths of migratory birds around tall lighted structures, and those of hatchling sea turtles disoriented by lights on their natal beaches. The more subtle influences of artificial night lighting on the behavior and community ecology of species are less well recognized, and constitute a new focus for research in ecology and a pressing conservation challenge. (Longcore & Rich 2004)

The amount of sonic energy released by human activity is recognized as an urban nuisance as well as an occupational safety concern. It also has recognized ecological effects: urban European robins have begun singing at night, when they have less acoustic competition. (Fuller et al 2007) Frogs have begun changing the pitch of their croaks in order to talk over traffic noise (Paris et al 2009)  In addition to sonic energy, human activity has released sonic memes into the environment. A meme is a self-replicating information pattern; jokes and computer viruses are two examples of memes. A person or computer acquires a meme and then spreads it, through retelling or infected emails. Sonic memes, such as ambulance sirens and cellphone ringtones, have been picked and repeated by songbirds. (Stover 2009) This is very interesting: human memes, the basis of Richard Dawkins’ ‘extended phenotype’ concept, have organically extended into other animals’ extended phenotype. (Recent reports of dolphins mimicking human speech are also very interesting in this context. The reverse flow also occurs, as animal communications are repackaged as ringtones or ambient music.)

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A companion article at ArkFab shares my thoughts on peer review in regards to this project and DIY/community/citizen science in general. 

At long last, the much-anticipated booklet, “CO2 Trouble: Ocean Acidification, Dr. Everett, and Congressional Science Standards” is available and approved for human consumption! Download and share HERE (or at Scribd HERE).

In this document, I have bundled, updated, and expanded my series of essays debunking the congressional testimony of Dr. John Everett regarding the environmental chemistry of carbon dioxide.

It has been designed to be a fairly short (less than 30 pages, including images, appendicies, etc.) and accessible read. It has been challenging but fun to write; I have had to learn a lot about GIMP, Python, Scribus, social networking, and of course ocean acidification to get to this point.

It was also very useful for me as an opportunity to go back through my earlier remarks and double-check my work. For example, I later realized that the documentation which Dr. Everett provides for his CO2 data in part two is ambiguous: Although the citation for the rate data is referred to as “Recent Global CO2”, the URL provided links to the longer record as measured at Mauna Loa Observatory. This confusion had led me in the past to make incorrect claims about some of the figures he presents. Ultimately it was inconsequential to my argument, but it was frustrating to have to deal with such ambiguities. On the other hand, this led me into comparing the Mauna Loa record with the global record (Appendix B) which was an interesting exercise.

In researching this project, I also came across new phenomena I wasn’t previously aware of. For example, while I was calculating historical rates of CO2 change, I ran though the 1000-year Law Dome record and saw this:

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I find some dry ice and hilarity ensues.

Veron JE, Hoegh-Guldberg O, Lenton TM, Lough JM, Obura DO, Pearce-Kelly P, Sheppard CR, Spalding M, Stafford-Smith MG, & Rogers AD (2009). The coral reef crisis: the critical importance of Marine pollution bulletin, 58 (10), 1428-36 PMID: 19782832

A part of my John Everett series – read more: 0/I – II.0 – II.5 – II.75 –  III.0 – III.3 – IV.0 – IV.4 – IV.8 – V – VII – VIII – Full Report 

The last part of Dr. Everett’s testimony presents his conclusions. Much of it is simply reiteration ofclaims he has already

Fig. 1. The rate of change in atmospheric carbon dioxide, based upon gas samples from three ice cores (Law Dome, Taylor Dome, and Vostok) and direct measurements at Mauna Loa Observatory. Data courtesy of NOAA Paleoclimatology and ESRL (see endnotes). Click for full.

made, but he also takes the opportunity to thicken the smoke screen just a little bit more. Some parts are mundane: ‘The most important approach [...] is to examine what happened during past times.’ I completely agree! See Fig. 1. But other parts are more problematic. Here’s a quick flyby:

He claims ‘There is no reliable observational evidence of negative trends that can be traced definitively to lowered pH of the water’, and dismissing experimental results. However, studies meeting his criteria exist, and they demonstrate negative consequences.

He demands that experiments be run over sufficient generations to allow for adaptation, but he doesn’t say how many generations are sufficient. This leaves any study demonstrating negative effects open to rejection by moving the goalposts for sufficient experimental length. Ironically, a paper which Dr. Everett had earlier claimed cast doubt upon acidification studies mentions the short time scales of current experiments, but concludes that it could well be masking the more severe effects of acidification:

‘Although suppression of metabolism under short-term experimental conditions is a “sublethal” reversible process, reductions in growth and reproductive output will effectively diminish the survival of the species on longer time-scales.’  (Fabry et al. 2008)

Conclusions he doesn’t like can be further dismissed: ‘If there were [an observation of deletrious effects of acidification], it would be suspect because there is insignificant change relative to past climates of the Earth.’ We have seen this statement to be simply incorrect. He fails to give further support for this position, stating that ‘Scientific studies, and papers reviewing science studies, have similar messages’, but not giving us any examples.

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Supposedly posts with images get all the clix. So here is an image. Via PictureIsUnrelated; clix for sauces.

Part VI of John Everett’s testimony is a criticism of a geoengineering approach to ocean acidification. I agree with his conclusion (that adding alkaline calcium carbonate to the oceans is not a useful approach to ocean acidification) but nevertheless find this section to be problematic. I’ll return to it once I’ve finished with the rest of his testimony.

Part VII is a collection of research suggestions “that would go a long way toward establishing the likely effects of an increased CO2 world.” On the surface, it’s hard to take issue with his suggestions, but in the context of the rest of his testimony, they ring rather hollow.

For example, his first research suggestion is the development of

“a CO2/temperature timeline based on extant research on past climates, at least back to about 600 million years before the present. This effort would provide a critical review of candidate papers and unpublished work that goes well beyond a typical peer-reviewed journal publication, or prior summary reports of the IPCC.”

I think that it would be great to have a comprehensive review of the state of paleoclimatology and paleogeochemistry. But Dr. Everett ignores what we already know about those topics- so what good would such an effort be?

Suggestion #2:

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A part of my John Everett series – read more: 0/I – II.0 – II.5 – II.75 –  III.0 – III.3 – IV.0 – IV.4 – IV.8 – V – VII – VIII – Full Report 

Part V of John Everett’s testimony (“Is this bad or good or just different?”) repeats several claims that we’ve already seen to be simply incorrect:

Little Rock Lake, site of a famous acid rain study. Image from Google Maps; sauceclick.

The only new evidence he presents in this section regards a different pH problem: acid rain.

“During the acid rain issues in the 1980s, a lake basin in Wisconsin was deliberately acidified (with EPA and NSF funding) to a pH of 4.7 then allowed to recover. ‘Some species were decimated and others thrived, but the sum-total of life in the lake stayed the same.’ This is a level of acidification 1,000 X the worst-case scenario for the oceans. It provides a clue as to what a 2X change might be.”

His reference for this claim is this news item from ScienceDaily. To clarify, when Little Rock Lake was ‘allowed to recover’, acidification was halted and its pH was allowed to rise to its previous levels. The news item is reporting on the slow recovery, which only took place once the acidification ceased. Dr. Everett presents a quote from this news item, which would seem to suggest that things were just fine in the acidified lake. In fact, the quote in its entirety refers to the lake’s recovery, rather than its acidified state:

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A part of my John Everett series – read more: 0/I – II.0 – II.5 – II.75 –  III.0 – III.3 – IV.0 – IV.4 – IV.8 – V – VII – VIII – Full Report 

We’ve seen that Dr. Everett’s discussion of paleogeochemistry fails to consider both rates of change and the geological record of ocean acidification. There is one last talking point in this section which requires comment:

“From 50-600 million years ago, atmospheric CO2 levels were usually 2-20 times higher than at present. [...] This included the age of the dinosaurs, when life was so prolific that we still use its carbon, limestone and chalk.”

Limestone and chalk, like corals and coccoliths, are made out of calcium carbonate. Many deposits of calcium carbonate occurred when there was much more carbon dioxide in the air. The Cretaceous is named after chalk deposits like the White Cliffs of Dover; CO2 levels during the Cretaceous were over 1000 ppm, compared to current levels around 390 ppm. If the ocean deposited calcium carbonate en masse during the high-CO2 Cretaceous, why should we expect it to become hostile to carbonates now?

The chalk cliffs of Dover, massive deposits of calcium carbonate from the high-CO2 Cretaceous. Is this a paradox? Not really. Click for sauce.

The answer lies, again, in time scales.

Over short time scales, like those on which acidification is currently occurring, the saturation state of calcium carbonate is determined by pH, which is controlled by CO2. However, on longer time scales, it’s controlled by another factor. As this article explains:

“Hence, the key, but rather counterintuitive result, is that on long time scales, ocean pH and atmospheric CO2 are decoupled from carbonate mineral saturation state, which is dictated primarily by weathering (in conjunction with the major cation [Ca2+, Mg2+] content of the ocean). Actually, saturation is not entirely decoupled geologically from pH and CO2, as all things being equal, at high CO2 (and a warmer climate), enhanced weathering requires higher carbonate burial and hence higher ocean saturation. Thus, the presence of “carbonate factories” with widespread CaCO3 production and burial is entirely consitent with a high CO2, low pH world. [...] Only in significant and geologically “rapid” departures from steady-state carbon cycling will both pH and saturation fall together…” (my emphasis)

In other words, over a long timeline, it’s the calcium that determines calcium carbonate favorability. Over short timelines, it’s the pH- and CO2 emissions are altering the pH on a short timeline.

A part of my John Everett series – read more: 0/I – II.0 – II.5 – II.75 –  III.0 – III.3 – IV.0 – IV.4 – IV.8 – V – VII – VIII – Full Report 

Last time we looked at Dr. Everett’s testimony, we examined his claim that, because carbon dioxide levels have been higher in the past, increasing levels are not alarming now. His argument is flawed, because although CO2 levels have changed, they usually change only very slowly. Now, they’re changing abruptly. Graphs of Deep Time can be intuitively misleading, because they collapse time scales and it can be hard to compare the rates of change from one image to the next. For example, this next graph shows information that we have gathered from looking at  gasses trapped in Antarctic ice. It’s obvious that the climate changes over Deep Time- but is it obvious from this graph how historical rates of change compare to modern rates?

Paleoclimatic and paleogeochemical data gathered from the Vostok ice core. Temperature (red) and carbon dioxide (blue) go up and down on these time scales - but its the rate that really matters. Click for sauce.

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A part of my John Everett series – read more: 0/I – II.0 – II.5 – II.75 –  III.0 – III.3 – IV.0 – IV.4 – IV.8 – V – VII – VIII – Full Report 

People who minimize or deny the threat of climate change (or ocean acidification, as in part IV of Dr. Everett’s testimony) will often demand that the change be “unprecedented” – that nothing like it has ever happened before in Earth history. (eg, here) The reasoning seems to be that if there have been ecological events like anthropogenic climate change in the past, then current events must not be alarming, since life on earth has each time survived and recovered:

“We know that the Earth has seen these conditions before, and that all the same types of animals and plants of the oceans successfully made it through far more extreme conditions. ” – Everertt (part V)

 

This has always seemed to me like it’s setting the bar a bit low: Do we only become alarmed when faced with the possibility of sterilizing the planet? And considering the amount of violence which earth life has withstood over the ages, it doesn’t seem a very strong statement that human impact is unlikely to wipe it out.

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