Since the Industrial Revolution, atmospheric carbon dioxide levels have risen steadily. We know that the pH in the ocean has dropped at a corresponding rate during this period; the correlation between atmospheric CO₂ and surface ocean pH is strong.

Explore the CO₂ and Ocean pH learning tool and examine how surface ocean pH is influenced by atmospheric carbon dioxide levels. Click on one of the RCP projections in the 'Options' menu to see the pH that climate models project our oceans may have by the end of the century. Before moving on, answer the following questions:

• What will the surface ocean pH be when the atmospheric CO₂ concentration reaches 500 ppm? 750 ppm? 1000 ppm?
• What will the atmospheric CO₂ concentration be in 2100 if we follow the A1B scenario most closely?
• What will the surface ocean pH be in 2100 if we most closely follow the A1B scenario? The A1FI scenario?

Question: Describe two consequences of ocean acidification. Think biologically, socially, or even economically. Who in the world will be most affected by a more acidic ocean?