Why are the oceans becoming more acidic?

The Amount of carbon dioxide in the atmosphere is rising and the oceans absorb a lot of it. seawater reacts with it causing carbonic acid.

Humans produce too much carbon dioxide, and because of the chemical composition of water, more specifically, the water in the ocean, it is inclined to absorb it, thus making it acidic. Furthermore, human waste contributes to the acidity of the oceans.