"Rising ocean temperatures and increasing levels of ocean acidity — carbon dioxide absorbed as carbonic acid — are currently having devastating effects on ocean ecosystems."  Joe Sheldon, PhD

"On the pH scale, which runs from 0 to 14, solutions with low numbers are considered acidic and those with higher numbers are basic. Seven is neutral. Over the past 300 million years, ocean pH has been slightly basic, averaging about 8.2. Today, it is around 8.1, a drop of 0.1 pH units, representing a 25-percent increase in acidity over the past two centuries."  National Geographic

Notice that the average is 8.2 therefore, we can conclude that the ocean pH over the past 300 million years has been higher or lower than the average.  Notice that 7 is neutral therefore, anything less than 7 is more acidic.

Lions, tigers, and bears oh my!  Chicken Little describes it best, "The Sky is falling!"