Analysis of “Ocean acidification: yet another wobbly pillar of climate alarmism”

“In 2004, two NOAA scientists, Richard Feely and Christopher Sabine, produced a chart showing a strong correlation between rising atmospheric CO₂ levels and falling oceanic pH levels. But then, just over a year ago, Mike Wallace, a hydrologist with 30 years’ experience, noticed while researching his PhD that they had omitted some key information[…] his results were surprising: there has been no reduction in oceanic pH levels in the last -century.”

Tullio Rossi, Marine biologist, University of Adelaide:
This is plain wrong. Oceanic pH levels decreased by 0.1 units compared to pre-industrial levels. This corresponds to a 30% increase in acidity. For a primer on pH, see this NOAA explainer.
Peer-reviewed references:

• Doney et al (2009) Ocean acidification: the other CO₂ problem, Annual Review of Marine Science
• Raven et al (2005) Ocean acidification due to increasing atmospheric carbon dioxide, The Royal Society

Ken Caldeira, Senior Scientist, Carnegie Institution for Science:
This statement just flies in both the face of observational facts and a basic understanding of chemistry. I would love to hear a cogent explanation of how atmospheric CO₂ levels could rise over the course of a century without producing a decrease in ocean pH.
Observations near Hawaii and several other open ocean environments show clear decreasing trends in ocean pH. See, for example this report from the European Environment Agency.
It is one thing to challenge future projections, but rejecting well-established scientific facts is another thing entirely.

Figure: Decline in pH measured at the Aloha station as part of the Hawaii Ocean time-series. Source

Richard Feely, Senior Scientist, NOAA's Pacific Marine Environmental Laboratory:
Michael Wallace contacted Chris Sabine and myself several years ago and asked how to get access to historical pH measurements in the oceans so he could determine long-term trends of global ocean pH for himself. We directed him to both modern (as published in Feely et al., 2008) and historical pH measurements archived at the NOAA National Centers for Environmental Information. We cautioned him that the earlier data sets prior to 1989 had significant issues with data quality as described in the document that went along with the data set obtained from NCEI. Mr. Wallace went on to perform his analysis of the historical data without regard for the oceanographic community’s concerns about the data quality or for the proper methodology to perform this kind of analysis. He chose to publish his results within the context of an interview written by Marita Noon in the Farmington Daily Times. We responded by correcting the record by formally restating our concerns about Mr. Wallace’s incorrect use of the historical data on our website. In short, Wallace’s chart does not show any kind of useful trend in global ocean pH because the data he used, and the way he used them, were not appropriate for this kind of analysis. In the first place, the pH measurements prior to 1989 were not reliable enough to detect small pH changes over that period. In addition, companion meta data on sensor calibration, pH scales, and temperature corrections were not available. Finally, the data were so limited that no meaningful global averages could be determined. The article by Mr. Delingpole in The Spectator failed to address these important issues, as Philip Williamson correctly points out in his response to the article.

“Ocean acidification is the terrifying threat whereby all that man-made CO₂ we’ve been pumping into the atmosphere may react with the sea to form a sort of giant acid bath.”

Jean-Pierre Gattuso, Research Professor, CNRS, Université Pierre et Marie Curie and IDDRI:
That is incorrect. No peer-reviewed article claim that the ocean will become acid (pH < 7).

“‘Acid’ was chosen, Moore believes, because it has ‘strong negative connotations for most people’.”

Tullio Rossi, Marine biologist, University of Adelaide:
The terms acidification was not chosen for its negative connotation but rather because it defines the direction of change. Here is a simple example: when you describe the cooling of your coffee what term do you use? Cooling or un-warming? If the temperature is going down we say it is cooling. If the temperature is going up we say it is warming. The same applies to acidity. When the pH of something goes down we say that it is acidifying. That simple.

“so more correctly it should be stated that the seas are becoming slightly less alkaline.”

Adam Subhas, PhD candidate, Caltech:
This is actually not correct. Invasion of CO₂ into the ocean does not change its alkalinity at all. By adding carbonic acid, and keeping alkalinity constant (defined as either the difference between dissolved cations and anions, or the excess of acid-base species at the CO₂ equivalence point), the pH decreases.

“seawater has a large buffering capacity which prevents dramatic shifts in pH;”

Adam Subhas, PhD candidate, Caltech:
This is true; however, the amount of CO₂ emitted by humans is also massive, a large portion of which has already been absorbed by the oceans. Since pH is relatively insensitive to changes in CO₂, it is often not the right parameter to look at in the whole system. For example, over the range of pH values which the author states are found in natural seawater, the surface pCO₂ changes from 180 ppm (pH 8.3) to 1500 ppm (pH 7.5). Thus, a mean change in ocean pH of 0.3 pH units represents almost a tripling of seawater pCO₂.

“[…]The impact on calcification, metabolism, growth, fertility and survival of calcifying marine species when pH is lowered up to 0.3 units […] is beneficial, not damaging. Marine life has nothing whatsoever to fear from ocean acidification.”

Ken Caldeira, Senior Scientist, Carnegie Institution for Science:
There is much evidence available to falsify this statement. Many experiments have shown substantial negative biological responses at these levels of pH change. Of course, some organisms are relatively unaffected by these levels.

An older review that is available here without a paywall:

• Langdon (2002) Review of experimental evidence for effects of CO2 on calcification of reef builders. In Proc. 9th Int. Coral Reef Sym.

“Then it will destroy all the species that depend on it — causing an almighty mass extinction which will wipe out the fishing industry and turn our oceans into a barren zone of death.”

That is not a truthful summary of the scientific literature. Check, for example, the meta-analysis of Kroeker et al. (2013) who describe processes and organisms that do not seem to be affected by ocean acidification.

• Kroeker et al. (2013) Impacts of ocean acidification on marine organisms: quantifying sensitivities and interaction with warming. Global Change Biology.

“a killer analysis conducted by Craig Idso of all the studies which have been done on the effects of reduced pH levels on marine life.”

Jean-Pierre Gattuso, Research Professor, CNRS, Université Pierre et Marie Curie and IDDRI:
This publication is not peer-reviewed, cherry-picks articles and does not involve proper statistical testing. It does not, therefore, qualify as a “killer analysis”! The comprehensive metanalysis that was performed by Kroeker et al. (2013) revealed decreased survival, calcification, growth, development and abundance in response to acidification when the broad range of marine organisms is pooled together. However, the magnitude of these responses varies among taxonomic groups.

• Kroeker et al (2013) Impacts of ocean acidification on marine organisms: quantifying sensitivities and interaction with warming. Global Change Biology.

Richard Feely, Senior Scientist, NOAA's Pacific Marine Environmental Laboratory:
The Idso meta-analysis described by Delingpole was never published. It does not take into account the proper method of proportional scaling analysis. It does not demonstrate how negative effects will impact ecosystem services and food-web processes that can have an effect on economically important fish and shellfish. It does not address the impacts we are already seeing on important fish food, such as pteropods (see Bednarsek et al., 2012, 2014; Feely et al., 2016). There are several highly credible published meta-analysis studies (Kroeker et al. ,2013; Wittman & Pörtner, 2013; and Busch and McElhany, 2016) that have told a much different story than Idso’s unpublished work. Delingpole failed to even mention these other studies, which show very significant impacts on several marine taxa. In summary, Delingpole’s article demonstrates a complete lack of appreciation of scientific literature on this topic and the proper choice of scientific methods for data analysis and synthesis that leads to a more accurate understanding of the present-day and future impacts of ocean acidification.

• Bednaršek et al (2012) Extensive dissolution of live pteropods in the Southern Ocean, Nature Geoscience
• Bednaršek et al (2014) Limacina helicina shell dissolution as an indicator of declining habitat, Proc. of the Royal Society B
• Feely et al (2016) Chemical and biological impacts of ocean acidification along the west coast of North America, Estuarine, Coastal and Shelf Science

“First, marine species that calcify have survived through millions of years when CO₂ was at much higher levels; second, they are more than capable of adapting — even in the short term — to environmental change”

Ken Caldeira, Senior Scientist, Carnegie Institution for Science:
Many marine organisms respond to changes in calcium carbonate mineral saturation states. These depend not only on pH, but also on factors including amounts of carbon and calcium in the ocean. One of the most important factors is ocean alkalinity, which varies on time scale of many thousands of years. In the geologic past, when atmospheric CO₂ was high, ocean alkalinity was also high, and so carbonate mineral saturation states could remain high.

Unfortunately, on the timescale of centuries or decades, changes come too fast for the ocean’s natural processes to buffer ocean carbonate mineral saturation states.

Directly comparing effects of high CO₂ levels that developed in the geologic past over many millions of years with high CO₂ levels developing today over decades and centuries shows a fundamental lack of understanding of well-established global geochemical cycles. This open access article explains some of the relevant chemistry:

• Cao et al (2016) Simulated effect of deep-sea sedimentation and terrestrial weathering on projections of ocean acidification, Journal of Geophysical Research Oceans

Jean-Pierre Gattuso, Research Professor, CNRS, Université Pierre et Marie Curie and IDDRI:
Some calcifying species were indeed abundant in the Cretaceous, a time at which the atmospheric CO₂ concentration was high. However, seawater alkalinity was also high due to intense weathering on land. Hence, the concentration of carbonate ions (CO₃, which controls calcification) was elevated. That compensation does not happen today and will not happen in the near future because total alkalinity does not change significantly on time scales of centuries. There is ample evidence in the literature for that.

Some fast-growing species are indeed able to develop some level of adaptation after several hundreds of generation. Overall, there is evidence that all past episodes of ocean warming, acidification and deoxygenation have led to mass extinctions. Furthermore, there is no calcifier close to CO₂ vents, suggesting that adaptation has limited capabilities.

“if oceans do become warmer due to ‘climate change’, the effect will be for them to ‘outgas’ CO₂, not absorb more of it”

Jean-Pierre Gattuso, Research Professor, CNRS, Université Pierre et Marie Curie and IDDRI:
Incorrect: The effect of warming is completely overwhelmed by the effect of increased atmospheric CO₂. Hence, the ocean will continue to absorb massive amounts of CO₂ in the future, despite ocean warming.

“[ocean acidification was ] First referenced in a peer-reviewed study in Nature in 2003”

Jean-Pierre Gattuso, Research Professor, CNRS, Université Pierre et Marie Curie and IDDRI:
The expression “ocean acidification” was actually introduced in 2001 by Broecker and Clark*. But the chemical processes involved have been know for a very long time at least the 1950s) and the impact of low pH (elevated acidity) on marine organisms since the early 1900s. The earliest experiments even predate the definition of pH by Sørensen in 1909.

• Broecker & Clark (2001) A dramatic Atlantic dissolution event at the onset of the last glaciation, Geochemistry Geophysics Geosystems

“Howard Browman, a marine scientist for 35 years, has published a review in the ICES Journal of Marine Science of all the papers published on the subject. His verdict could hardly be more damning. The methodology used by the studies was often flawed; contrary studies suggesting that ocean acidification wasn’t a threat had sometimes had difficulty finding a publisher. There was, he said, an ‘inherent bias’ in scientific journals which predisposed them to publish ‘doom and gloom stories’.”

Howard Browman, Principal Research Scientist, Norwegian Institute of Marine Research:
The following decomposition of this excerpt from Mr. Delingpole’s article in The Spectator identifies inaccuracies in his reporting that lead to misrepresentation of the content and intent of my article. Importantly, Mr. Delingpole never contacted me to verify that his reporting on my article was accurate. Nor was I contacted by the UK’s Independent Press Standards Organisation during their investigation of the accuracy of Mr. Delingpole’s article in The Spectator.