New Study: Rising CO2 levels will deafen “Nemo!”

CO2 deafens “Nemo” – or, how many ichthyologists can you fit in that car?

Posted on June 4, 2011 by Anthony Watts

We’ve already had a “climate craziness of the week” so I’ll just file this bit of blather under another category. First, this article in The Independent, which aims to scare the children.



The paper was published in Biology Letters… ‘Ocean acidification erodes crucial auditory behaviour in a marine fish’ by Steve Simpson, Philip Munday, Matt Wittenrich, Rachel Manassa, Danielle Dixson, Monica Gagliano and Hong Yans.

As anthropogenic global warming continues to implode like the Ptolemaic Solar System, ocean acidification (AKA Chicken Little of the Sea) will become the primary carbon boogeyman and the Enviromarxists preferred crisis du jour.

How Dangerous is Chicken Little of the Sea to poor little Nemo?

Ocean acidification can only occur if Dissolved Inorganic Carbon (DIC) is rising faster than Total Alkalinity (TA). This nomogram demonstrates the relationship of TA & DIC to pH…

According to Dore et al., 2009, “Over the past 250 years, the mean pH of the surface global ocean has decreased from ≈8.2 to 8.1… This acidification of the sea is driven by the rapidly increasing atmospheric CO2 concentration, which results from fossil fuel combustion, deforestation, and other human activities. Models predict that surface ocean pH may decline by an additional 0.3–0.4 during the 21st century”… A total pH decline of 0.4 to 0.5 (8.2 to 7.7 or 7.6).

I used a linear regression to estimate TA and DIC at ~275 and ~550 ppmv…

If I plot their in situ TA vs in situ DIC and extrapolated it as above (red curve), I get a very strong correlation (R^2=0.72); but I don’t get anything close to a 0.5 to 0.6 pH decline from a doubling of pre-industrial CO2 levels. I get a total decline of 0.16 (8.30 to 8.14) due to a doubling of pre-industrial atmospheric CO2 levels.

The only way I get a pH decline comparable to 0.4 to 0.5 is when I use the TA and DIC values that were normalized to a salinity of 35 (blue curve). This yields a pH decline of 0.44 (8.40 to 7.96); but it is a horrible correlation (R^2=0.05). TA and DIC are highly correlated to salinity(R^2=0.88, 0.74). DIC has a moderate correlation (R^2=0.39) and TA has a weak correlation (R^2=0.12) to atmospheric CO2. The normalization of TA and DIC to a constant salinity subdues the buffering provided by salinity; while amplifying the acidification effect of increasing CO2. A realistic treatment of salinity, yields an insignificant lowering of pH from a doubling of pre-industrial CO2. Chicken Little of the Sea does not appear to be very dangerous.

Pelejero et al., 2005 demonstrated that the pH of seawater in the vicinity of the Great Barrier Reef (GBR) fluctuates on a cycle correlative to the PDO. The oscillation has a period of ~50 years and an amplitude of ~0.3 pH units. The study in question suggests that the total acidification caused by a doubling of pre-industrial CO2 will be less than the amplitude of the natural pH cycle. Nemo has “already been there” and “done that” many times before.

If Nemo really is deafened by pH fluctuations… How did he survive the natural pH oscillation demonstrated by Pelejero?


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