The concentration of carbon dioxide in the atmosphere is linked to chemical changes in the world's oceans.
The graph below shows how atmospheric carbon dioxide concentration and ocean surface pH changed between the years 1960 and 2020.

Describe the relationship between the atmospheric carbon dioxide concentration and the pH of the ocean surface water.
Describe and explain the link between the atmospheric carbon dioxide concentration and the concentration of hydrogen ions, H+\text{H}^+H+, in the ocean water.
Use the graph to estimate the year in which the atmospheric carbon dioxide concentration was 370 ppm370\text{ ppm}370 ppm.