Over the 20th Century the PH of Seawater Has Decreased

Question

Over the 20th century the pH of seawater has decreased by:
A) 0.001
B) 0.01
C) 0.1
D) 0.2
E) 1.0

Accepted Answer

The pH of seawater has decreased by approximately 0.1 over the 20th century, primarily due to the absorption of carbon dioxide from the atmosphere, which forms carbonic acid in water and lowers its pH.