Ocean Acidification Calculator Formula
Understand the math behind the ocean acidification calculator. Each variable explained with a worked example.
Formulas Used
Estimated Current pH
estimated_ph = ph_preindustrial - ph_droppH Decrease
ph_change = ph_dropH+ Ion Increase
h_ion_increase_pct = (pow(10, ph_drop) - 1) * 100Variables
| Variable | Description | Default |
|---|---|---|
co2_preindustrial | Pre-industrial CO2(ppm) | 280 |
co2_current | Current CO2(ppm) | 420 |
ph_preindustrial | Pre-industrial Ocean pH | 8.18 |
ph_drop | Derived value= 0.85 * log(co2_current / co2_preindustrial) / log(10) | calculated |
How It Works
Ocean Acidification and CO2
When CO2 dissolves in seawater it forms carbonic acid, lowering the pH. The ocean has absorbed about 30% of human-produced CO2.
Simplified Formula
Delta pH = 0.85 x log10(C / C0)
Where C and C0 are current and pre-industrial CO2 levels. The coefficient 0.85 approximates the buffering chemistry of seawater (the Revelle factor). Since pH is logarithmic, even a small drop represents a large increase in acidity.
Worked Example
CO2 has risen from 280 ppm to 420 ppm with pre-industrial pH of 8.18.
- 01CO2 ratio = 420 / 280 = 1.5
- 02log10(1.5) = 0.1761
- 03pH drop = 0.85 x 0.1761 = 0.1497
- 04Estimated pH = 8.18 - 0.150 = 8.030
- 05H+ increase = (10^0.150 - 1) x 100 = 41.3%
Frequently Asked Questions
Why is ocean acidification dangerous?
Lower pH reduces the availability of carbonate ions that corals, shellfish, and plankton need to build shells and skeletons. This threatens entire marine food webs.
How much has ocean pH dropped?
Ocean surface pH has fallen from about 8.18 to 8.07 since the pre-industrial era, a 30% increase in hydrogen ion concentration.
Can the ocean keep absorbing CO2?
The ocean is a finite buffer. As it acidifies, its capacity to absorb additional CO2 decreases, which could accelerate atmospheric warming.
Ready to run the numbers?
Open Ocean Acidification Calculator