Ray, Average ocean pH has increased by about 0.1, from a pre-industrial pH of about 8.16 to a current pH of 8.07, still slightly basic (https://www.epa.gov/ocean-acidification/understanding-science-ocean-and-coastal-acidification). Atmospheric CO2 has increased about 40%. I am not sure how to understand "a third more acidic." Converting the pH to hydrogen ion concentration (pH is a log function), I calculate that there has been an increase of 25% in that concentration. Maybe that's what you meant. In relation to shell deposition, as the pH become lower (more acidic) the equilibrium between solid and dissolved calcium carbonate is moved toward higher solubility, making it more difficult to deposit as shell.
I think we need to separate two different rates that affect CO2 concentrations. One is the rate of addition by the burning of fossil fuels, deforestation,etc., and the other is the rate of CO2 removal by the weathering of basic rocks. Because the first rate is currently (and unnaturally) very high, it overwhelms the rate of removal by weathering, and we get the observed increase in atmospheric CO2. As far as I know, the geological process of weathering has been little affected by human activity. Perhaps my account didn't make these rate differences clear.
Walter, I had been lead to believe the ocean is far more acidic now than before the industrial age, a figure of roughly a third more is bandied about. And the Keeling or Keeler curve of atmospheric CO2 has been steadily rising with fossil fuel use, industrialization and such. Now over 400 ppm and rising. The CO2 extant now would need to be absorbed in the oceans and then turned to calcium carbonate then into shells of various types, eventually falling to the ocean floor and becoming limestone over centuries. Seems simplistic compared to your account, and maybe inaccurate, but as I read your version of events, it seemed the balance was toward a lower atmospheric CO2 and that is not what is being measured from the relatively pristine heights of Hawaii. Am I way off?
Ray, Average ocean pH has increased by about 0.1, from a pre-industrial pH of about 8.16 to a current pH of 8.07, still slightly basic (https://www.epa.gov/ocean-acidification/understanding-science-ocean-and-coastal-acidification). Atmospheric CO2 has increased about 40%. I am not sure how to understand "a third more acidic." Converting the pH to hydrogen ion concentration (pH is a log function), I calculate that there has been an increase of 25% in that concentration. Maybe that's what you meant. In relation to shell deposition, as the pH become lower (more acidic) the equilibrium between solid and dissolved calcium carbonate is moved toward higher solubility, making it more difficult to deposit as shell.
I think we need to separate two different rates that affect CO2 concentrations. One is the rate of addition by the burning of fossil fuels, deforestation,etc., and the other is the rate of CO2 removal by the weathering of basic rocks. Because the first rate is currently (and unnaturally) very high, it overwhelms the rate of removal by weathering, and we get the observed increase in atmospheric CO2. As far as I know, the geological process of weathering has been little affected by human activity. Perhaps my account didn't make these rate differences clear.
Lovely, graceful lessons. Thank you for including us in the list.
Eric
Walter, I had been lead to believe the ocean is far more acidic now than before the industrial age, a figure of roughly a third more is bandied about. And the Keeling or Keeler curve of atmospheric CO2 has been steadily rising with fossil fuel use, industrialization and such. Now over 400 ppm and rising. The CO2 extant now would need to be absorbed in the oceans and then turned to calcium carbonate then into shells of various types, eventually falling to the ocean floor and becoming limestone over centuries. Seems simplistic compared to your account, and maybe inaccurate, but as I read your version of events, it seemed the balance was toward a lower atmospheric CO2 and that is not what is being measured from the relatively pristine heights of Hawaii. Am I way off?