[Chondrally (OP)]

There was originally a mistake in the CO2 concentrations around 2021 based on ICPP data, that has now been corrected.

At 1376 ppm CO2 in the atmosphere, most likely around 2230 to 2240, the calcium carbonate buffer in the ocean will begin to break!

The following links are topical for environmental and civilization sustainability.  The first one is about the breaking of the magnesium  buffer in the ocean at 493 ppm of CO2 in the atmosphere  around 2052 and how this will affect the pH of the ocean,  and how this in turn will affect the base of the food chain in the ocean, threatening life on the planet in a severe way.  The second is about a possible solution to the problem, creating a super efficient natural gas- solar engine that emits no CO2,  and that could revolutionize energy and transportation globally.  The west probably won't do it due to the power of the oil cartels and auto companies and their cash cow status quo.  But China and india might do it,  forcing the west to follow suit.

http://www.thenakedscientists.com/forum/index.php?topic=53181.0
http://www.thenakedscientists.com/forum/index.php?topic=53180.0




When the calcium carbonate buffer begins to break at 1376 ppm CO2 in the atmosphere at sea level,  around 2240 annum,  the ocean will start to off gas CO2 into the atmosphere in small quantities at first leading to  large quantities eventually and stop overall absorbing CO2.  Deep ocean currents will well up from the depths and off gas CO2 into the atmosphere more often after this date than previously for a net weather effect.

Around 2240 annum, at around 1376 ppm CO2 in the atmosphere a serious nonlinearity in the equations governing diffusion and CO2 in the atmophere occurs,  and a sharp pH change will occur in the next 10 years affecting all life in the ocean, and possibly all life on the planet because of ecosystem linkages and the interconnectedness of the food chain.  Weather will be affected.   Unless something drastic occurs in technology before then to prevent the further net emission of CO2 into the atmosphere from the economy, reforestation, and population checks due to developing world initiatives.

The  engine mentioned in the Technology section of naked scientists.com that is super fuel efficient and emits only trace waste gases including no CO2 to the atmosphere while emitting trace amounts of carbon monoxide and nitrous oxides,  with no net O2 consumption from the atmosphere could really help the situation to save the oceans,  but it would be possibly harmful for the oil economy and global stability.  It is a challenge of the 21st century to ensure economic stability and achieve a technologically safe earth that isn't harmful to the creatures that live here.  It would be a bad metaphor to our future if we went to the stars but our home world died because we couldn't figure out how to save her in time!  The knowledge is available,  we need political will and international cooperation and trust to solve this problem.






the pH solution that is  presented is essentially a mass and charge balance.

The forecast for the ppm CO2 in the atmosphere from Scripps Oceanographic institute is begun with,   A longer term forecast is carried further out to 2400, assuming we continue as we are going..... which we wont , as there will be improvements like the blue diesel mentioned by Audi, and my engine which is zero CO2 emissions......

http://www.thenakedscientists.com/forum/index.php?topic=53180.0



however, its the most prudent guess right now.

Then the GT-C(mass of CO2 carbon)  in the atmosphere is solved for based on (Boyles Law)PV=NRT and gravity and density with height.

Then the ppm CO2 at sea level is used and an iterative solution of the diffusion equations for equilibrium at the surface is carried out. Solving for equilibrium using gravity and pressure and temperature and salinity gradients with depth and solving the ksp solubility product equations for the concentrations of ions with depth at the balance CO2 concentrations and the buffer equations is carried out.... to get the pH with depth. Very small discrete steps with depth were used, and quite a bit of effort went into finding a good and accurate step size.

The average of all the pHs over 1000 metres to get an average pH in shallow is reported.

ksp solubility product equations are actually behaving like 3D or 4D hyperbolas depending on the formula. Normally, as you start out on one section of the hyperbola, the gradient for the pH is always decreasing as CO2 increases, but as it passes the knee of the hyperbola, The concentrations of the buffer equations all start to behave differently in a nonlinear manner.

When this happens, the pH increases instead, and can increase quite dramatically over short periods of time or even decrease dramatically as the case may be.Another way to look at it is that there is a pool of ions fed from 2 or 3 reactions that cascade when the equilibrium is broken by the injection of carbonic acid ions into the solution. This cascade neutralizes the acid by introducing OH- or hydroxyl ions into solution that neutralize or balance the pH.  Each buffer has a finite buffering capacity, and it is cumulative. Once the buffering capicity limit is reached we say the buffer is spent or broken. After this, the pH can change rapidly.

Once the buffer is broken,  the pH does react very differently after the knee of the hyperbola is passed and the buffer equations solution from the ksp solubility products behave very differently too..
 The capacity of the buffer to neutralize added acid or added base is compromised at that region of the curve.







When the chemical potential of a dissolved chemical species exceeds that of the same species in solid form then the system will deposit solid(precipitate-sea snow-calcium carbonate) until equilibrium is regained and thereby the system free energy is minimised.  Of course that is only one side of the equilibrating system that we are dealing with.  This was not modeled in this system,  and precipitation is always notoriously difficult to model and involves quantum mechanics and Chaos Theory..  Its time to focus on solutions that give us real hope.  We know the oceans will have a problem with pH and off gasing, affecting the food chain, life in the ocean, and the global weather.  Only solutions that can stop CO2 emissions,  while maintaining our standard of living and mobility will work.  The engine that emits no CO2 or is CO2 neutral is our best hope.  The natural gas -solar or nuclear hybrid engine that is super fuel efficient and only emits trace amounts of carbon monoxide and nitrous oxides and is oxygen neutral offers us real hope.  Lets hope saner minds prevail and that reason amounts to something.


The following buffers exist in the ocean:
CO2(g) + 2e- -> CO2(2-)(aq)      first of all 2 electrons are stolen and there is a charge balance in the ocean
                                              so this results in the buffers producing more protons to balance the charge
Mg(2+) + CO2(2-) <-> MgCO2    the magnesium and calcium carbonate buffers steal CO2(2-) and cause sea snow which drops to deeper depths where it redissolves back into Mg(2+) and CO2(2-) under pressure.
CO2(2-)+H+ <-> HCO2(-)          a proton is stolen, resulting in more  hydroxyl radicals than protons.....
HCO2(-)+H+ <-> H2CO2            another proton is stolen resulting in more hydroxyl radicals than protons.
So the net effect of carbonic acid is to first steal 2 electrons from the ocean,  resulting in buffers that either reduce the amount of hydroxl radical in the ocean or produce more protons to balance the charge.
next protons are stolen,  resulting in buffers that either replace the protons or reduce the hydroxyl radicals or reduce other negative ions in the ocean (most likely) resulting in a net surplus of hydroxyl radicals and a net increase in pH making the ocean more basic.  which is what the following data are saying in effect.
H+ + OH- <-> H2O    OH steals an electon from H2O and yields a proton and a hydroxyl radical affecting pH or
H+ and OH- combine and form H2O with a net charge change of zero to the charge balance.
Ca(2+)+2HCO2(-) <-> Ca(HCO2)2  the formation of magnesium and calcium bicarbonate and also its sea snow.
Boron ions, Sulphates (Sulphuric acid and Phosphates (Phosphoric acid).

Question 1:  Where do the 2 electrons come from?,  currents in the oceans and lightning. creating storms and charge imbalances.....
Question 2:  which species replace the charge in the charge balance?  most likely phosphates, sulphates and boron complexes and magnesium carbonate and calcium carbonate.
If the charge is balanced by other species,  then there will be an imbalance of H+ and OH- and H2O resutling in a pH imbalance.

It appears from the following data that the net effect of introducing gaseous CO2  in the ocean past 2090-2100 and 878 ppm CO2 in the atmosphere,  is that the ocean becomes more basic, higher pH without bound, also killing the ocean and all marine life, affecting the weather as well and the temperature.





shallow    
water   
minimum   
pH   Year
SWS scale   
   
8.48011   1970
8.47634   1975
8.47212   1980
8.46762   1985
8.46294   1990
8.45821   1995
8.45357   2000
8.44860   2005
8.44351   2010
8.43922   2015
8.43530   2020
8.43183   2025
8.42936   2030
8.42823   2035
8.42841   2040
8.43061   2045
8.45291   2050
7.92934   2055
7.92534   2060
7.92111   2065
7.91641   2070
7.91145   2075
7.90590   2080
7.90013   2085
7.89419   2090
7.88790   2095
7.88180   2100
7.87519   2105
7.86870   2110
7.86236   2115
7.85620   2120
7.85026   2125
7.84456   2130
7.83908   2135
7.83360   2140
7.82700   2145
7.75431   2150
7.83120   2155
7.82557   2160
7.82259   2165
7.82064   2170
7.81940   2175
7.81874   2180
7.81922   2190
7.82097   2200
7.82581   2210
7.82463   2220
7.82387   2230
8.64108   2240
8.67203   2250
8.73166   2260
8.81154   2270
8.90850   2280
9.01704   2290
9.12988   2300


ocean hold            
top 1000 metres   total ocean   atm   ppm   
GT -C   GT-C   GT-C      YEAR
773.28   2870.77   467.92   326.95196   1970.000
775.61   2878.62   476.32   332.82085   1975.000
777.92   2886.36   485.60   339.31052   1980.000
780.25   2894.12   495.77   346.41468   1985.000
782.65   2902.06   506.81   354.12709   1990.000
785.12   2910.18   518.71   362.44147   1995.000
787.67   2918.50   531.46   371.35154   2000.000
790.24   2926.93   545.06   380.85105   2005.000
792.78   2935.29   559.49   390.93372   2010.000
795.39   2943.71   574.74   401.59329   2015.000
798.06   2952.35   590.81   412.82349   2020.000
800.81   2961.21   607.69   424.61804   2025.000
803.61   2970.18   625.37   436.97068   2030.000
806.58   2979.63   643.84   449.87515   2035.000
809.72   2989.59   663.09   463.32517   2040.000
813.04   3000.01   683.11   477.31447   2045.000
818.85   3013.13   703.89   491.83680   2050.000
819.44   3021.25   725.43   506.88586   2055.000
823.13   3032.69   747.71   522.45541   2060.000
826.54   3043.28   770.73   538.53918   2065.000
830.00   3054.01   794.48   555.13088   2070.000
833.48   3064.83   818.94   572.22426   2075.000
837.07   3075.85   844.11   589.81304   2080.000
840.69   3086.97   869.98   607.89097   2085.000
844.35   3098.21   896.55   626.45176   2090.000
848.12   3109.63   923.79   645.48915   2095.000
851.85   3121.09   951.71   664.99688   2100.000
855.81   3132.84   980.29   684.96867   2105.000
859.80   3144.70   1009.53   705.39826   2110.000
863.85   3156.68   1039.42   726.27938   2115.000
867.97   3168.79   1069.94   747.60575   2120.000
872.16   3181.05   1101.09   769.37112   2125.000
876.45   3193.47   1132.85   791.56920   2130.000
880.89   3206.09   1165.23   814.19375   2135.000
885.60   3219.04   1198.21   837.23848   2140.000
891.19   3232.93   1231.79   860.69712   2145.000
940.77   3290.87   1265.94   884.56342   2150.000
894.47   3252.98   1300.67   908.83109   2155.000
900.47   3267.44   1335.97   933.49388   2160.000
905.50   3280.98   1371.82   958.54551   2165.000
910.34   3294.38   1408.22   983.97972   2170.000
915.14   3307.78   1445.16   1009.79023   2175.000
919.95   3321.24   1482.63   1035.97078   2180.000
922.61   3323.68   1559.12   1089.42   2190.000
925.24   3326.07   1637.62   1144.27   2200.000
926.37   3326.97   1718.06   1200.47   2210.000
930.16   3330.53   1800.37   1257.98   2220.000
932.51   3332.65   1884.47   1316.75   2230.000
937.59   3337.50   1970.29   1376.72   2240.000
938.79   3338.47   2057.77   1437.84   2250.000
941.53   3340.98   2146.83   1500.07   2260.000
944.25   3343.47   2237.39   1563.35   2270.000
947.28   3346.26   2329.39   1627.64   2280.000
950.18   3348.94   2422.76   1692.88   2290.000
951.41   3349.93   2517.42   1759.02   2300.000