Some analysis was carried out with the Revelle factor and the uptake factor of oceanographic fame, both of which solve for the pH of the ocean based on CO2sys by Ernie Lewis and Doug Wallace from ORNL, extended to create a nonlinear differential equation that governs sea water pH relative to dissolved inorganic carbon concentrations (DIC) which changes with fugacity changes and depth, it was found that these two factors solved for about 103 GT of Total inorganic carbon in the top 1000 metres of the ocean. This number did not change much from year to year and equilibrium to equilibrium. This runs counter to the experimental evidence in Susan Libes text, ocean biogeochemistry which references work at Princeton on experimental data, which shows the shallow water above the knee of the thermocline holds about 800 GT of carbon as of 2006 globally.
While the thermocline knee changes locally, the median thermocline knee depth should be calculated from the world ocean database on a year by year basis, with limits of one standard deviation on either side, where the solution is recomputed to find the error bars. Much work remains to be done.
However, with several assumptions, a significant result has been found.
http://richardbelshaw.greenparty.ca/...
download this zip file and expand it to examine the .xls file that shows the path we might take if Obama's energy agenda is not followed.
It assumes peak oil, and a gradual levelling off of fossil fuel demand to about 10 GT of carbon output in CO2 form per year.
Methane measurements are also included as are N2O. I would like to thank the ministry of the environment of New Zealand for publishing its N2O measurements on the web. Previous articles give the references as ORNL for the CO2 data, and the origin of the methane data.
It seems that a temperature increase of about 4 degrees is to be expected due to CO2, methane and N2O by about 2087, however that upper limit as a median value would be moderated by the huge heat capacity of water vapour in the atmosphere.
The biggest result offered is that around 2047, plus or minus 7 years, at 506ppm +/- 72 ppm , the global ocean average pH in the shallow regions will suffer a severe and irreversible drop in pH readings and become more acidic and somewhat inhospitable to marine life. This was found after extensive laptop calculations in visual basic with the program module 'calcppm' (on setting '1'), which calculates the ocean pH profiles for the global ocean as one median pH profile, or center of mass of the system to a depth of 1000 m or 1 km, at intervals of 1/4 of a cm using a modified Runge-Kutta method and a technique to solve for dH/dA, the rate of change of hydrogen ion concentration with respect to DIC concentration.
Since the ocean reaches equilibrium with the atmosphere every 292 days approximately, within one year it would have reached equilibrium with the previous years CO2 output. This is still an approximation, but approximations need to be made, as the absorption of CO2 is a continual process, Libe and others assume that the ocean absorbs about 1/3 of all man made anthropogenic emissions per annum, the rest remaining in the atmosphere. I have followed that assumption here, which is based on ocean measurements, and is not in accordance with the Ravelle factor or the uptake factor either.
Please feel free to look at the charts in the program oceanconchdonothing2009_3.xls, copyright Richard J. Belshaw 2009
Here we can see many results.
The Omega calculation which calculates how the ocean carbonate, bicarbonate and dissolved CO2 gas in the ocean chemistry affect the precipitation or dissolution of calcite and aragonite (different forms of calcium carbonate) in the ocean. These are average values for the top 1000 metres, assuming the thermocline knee is at 1000 metres. It is more likely that the thermocline knee is between 500 and 800 metres, in which case the DIC and hydrogen ion concentrations would be more intense and we would expect the acidity drop sooner. More calculations need to be done, and i need help reducing data in the world ocean database, if any of you feel inclined, please contact me at chondrally@gmail.com to produce a work of teamwork.
Failing that it will take some time to make more progress.
It is generally accepted that the mixing between the shallow zone above the thermocline knee and the deep ocean water is restricted to zones where the ocean currents come to the surface like in the arctic atlantic, the arctic near the bering straits and in the southern ocean. I have already quoted in a previous diary the results of some AAAS scientists who have warned about pH dropping in the southern ocean around 450 ppm.
My result is more general and warns of a global ocean pH drop, a tipping point. While approximations are just that, the complexity of the ocean is almost without bound and many local effects occur, like el nino and la nina to site a couple. So it would not surprise me, and in fact i have heard Al Gore mention that there are zones in the pacific off the coast of california and BC that already have reduced pH measuring about 7.75
My pH calculations are on the total pH scale, following Lewis and Wallace on that one.
I have a maple applicaition that shows the development of the nonlinear differential equation governing pH changes relative to DIC changes that is available on demand for inspection.
Please feel free to criticize or comment as you see fit, i welcome commentary especially constructive commentary. This is still a work in progress.
Some assumptions made:
sources of error.....
- haven't used median ocean shallow water depth from world ocean database yet, unknown apriori and hard to compute.
- shallow water median depth could be from 500 to 800 metres, i have used 1000 metres.
- Revelle factor and uptake factor as referenced in texts are incorrect, they predict an ocean DIC content of 103 GT pretty constant and practically
no ocean absorbtion of CO2 over the years. if you set ffac=1 in the program calcppm module, you will get the Revelle factor solution.
- texts say ocean absorbs one third of annual antrhopogenic CO2 emissions, have assumed this to be true.
- texts say shallow water holds 800 GT of dissolved inorganic carbon as of 2006, have assumed this to be true
- there is very little mixing in the ocean below the thermocline knee of long lived deep water and shallow water, except through ocean currents in the sourthern ocean and arctic, where the deeper ocean currents come to the surface and interact with CO2 in the atmosphere.
Pluses
I have used information from CO2sys by Ernie Lewis and Doug Wallace of ORNL (Oak Ridge National Laboratory) in developing a nonlinear differential equation that governs pH change with dissolved inorganic carbon (DIC) concentration, which changes with depth.
I have used a modifed Runge Kutta nonlinear equation solving technique to compute pH at each .25 cm of a total of 1000 metres deep
i have used Booles approximation to numerically integrate the DIC with depth and the gases in the atmosphere. Every 10 cm a reading is produced for the ocean, and every 1metre a reading is produced to an altitude of 44400 metres in the atmosphere.
best regards,
Chondrally