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Monday, June 7, 2010

John Abraham guest posts on Skeptical Science: Monckton Chronicles Part III – Acid Reflux?

Monckton Chronicles Part III – Acid Reflux?

Guest post by John Abraham, Skeptical Science, June 8, 2010

This time, we are turning our attention to a problem that is rapidly gaining attention in the public arena. That problem, commonly termed “ocean acidification” refers to the lowering of the ocean’s pH by the dissolution of carbon dioxide in seawater. It should be noted that the ocean is basic (its pH is greater than 7). Ocean “acidification” does not refer to the ocean becoming an acid. It means the ocean is becoming less basic.

Scientists believe that the pH of the ocean has decreased by about 0.1 point since pre-industrial times. This may not sound like a large change, but it must be recognized that the pH scale is logarithmic. On a log scale, a change in pH of 0.1 means that the concentrations of hydrogen ions in the water has changed by about 30%.

So, why does the decrease in pH concern us? In saltwater, living creatures that make calcium carbonate shells or skeletons (oysters, clams, sea urchins, corals, etc.) require a pH around 8.2. When pH falls too low, these creatures have difficulty making and maintaining their shells.

Some people, including Chris Monckton, have argued that as the ocean warms, it will release excess carbon dioxide into the air and thereby will maintain a relatively stable pH level. It turns out that the impact of the increase of carbon dioxide in the atmosphere will far outweigh the decreased solubility of carbon dioxide in seawater due to the temperature change.

Some people, including Mr. Monckton, believe that natural weathering processes will maintain the pH level of the ocean at today’s values. It turns out this is highly unlikely because of the very slow rate at which weathering occurs.

Some people, including Mr. Monckton, believe that ocean acidification is “rubbish”. It turns out that most scientists who really study this issue do not agree with him. Several U.S. and European scientists recently co-authored an article titled “frequently asked questions about ocean acidification” which was published by the U.S. Ocean Carbon and Biogeochemistry program.

Here are some of the researchers statements who disagree with Mr. Monckton. Full citations are given so that you can access and read these articles yourself. Sample quotations have been extracted from the articles and are shown below the citations. Finally, URL links have been provided. An excellent volume on ocean acidification and its impacts on marine organisms can be found at:

O. Hoegh-Guldberg et al., Coral Reefs Under Rapid Climate Change and Ocean Acidification, Science, 318, 1737-1742, 2007.
Under conditions expected in the 21st century, global warming and ocean acidification will compromise carbonate accretion, with corals becoming increasingly rare on reef systems.”
V. Fbary, B. Seibel, R. Feely, and J. Orr, Impacts of Ocean Acidification on Marine Fauna and Ecosystem Processes, ICES J. Marine Science, 65, 414-432, 2008.
Oceanic uptake of anthropogenic carbon dioxide (CO2) is altering the seawater chemistry of the world’s oceans with consequences for marine biota.”
K. Anthony, et al., Ocean Acidification Causes Bleaching and Productivity Loss in Coral Reef Builders, Proc. Nat. Acad. Sciences, 105, 17442-17446, 2008.
Ocean acidification represents a key threat to coral reefs by reducing the calcification rate of framework builders.”
S. Doney et al., Ocean Acidification, the Other CO2 Problem, Ann. Rev. Marine Science, 1, 169-192, 2009.
Rising atmospheric carbon dioxide (CO2), primarily from human fossil fuel combustion, reduces ocean pH and causes wholesale shifts in seawater carbonate chemistry. The process of ocean acidification is well documented in field data, and the rate will accelerate over this century unless future CO2 emissions are curbed dramatically. “
Guinotte and V. Fabry, Ocean Acidification and Its Potential Effects on Marine Ecosystems, Ann. NY Academy of Science, 1134, 320-342, 2008.
Ocean acidification is rapidly changing the carbonate system of the world oceans.”
B. McNeil, R. Matear, Southern Ocean Acidification: A Tipping Point at 350ppm Atmospheric CO2, Proc. Nat. Acad. Sci., 105, 18860-18864, 2008.
Southern Ocean acidification via anthropogenic CO2 uptake is expected to be detrimental to multiple calcifying plankton species by lowering the concentration of carbonate ion (CO32?) to levels where calcium carbonate (both aragonite and calcite) shells begin to dissolve.”

Once again, we see that the science community disagrees with the interpretation of Christopher Monckton. Ocean acidification is an issue that scientists are concerned about and it is just one more reason to get serious about reducing greenhouse gas emissions.


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