# How can human activities change the pH of the environment?

Well, there are some data to suggest that increased concentrations of atmospheric $C {O}_{2}$ has increased the $p H$ of the oceans.
$C {O}_{2}$ is an acidic oxide, whose acidic behaviour may be represented by the following equation:
$C {O}_{2} \left(g\right) + {H}_{2} O \left(l\right) r i g h t \le f t h a r p \infty n s {H}_{3} {O}^{+} + H C {O}_{2}^{-}$
Oceanic $p H$ levels may have increased over an historical time period. The depletion of the world's coral reefs is a direct consequence of ocean acidity.