In chemistry, a water-based solution can be acidic or alkaline (basic), which is determined by pH scale. The scale has 14 levels, with 7 being neutral. The values below 7 indicate that the solution is acidic – the lower the number, the higher the acidity. The values above 7 indicate that the solution is basic or alkaline. With increasing alkalinity, as the number increases.
For the past few hundred million years, the ocean’s average acidity has been around 8.2, which is moderately alkaline (moderately basic). However, the current pH level of the ocean saw a drop of 0.1, which means a 30% increase in acidity (the scale is logarithmic). Ocean acidification is, therefore, reduction of its pH or alkalinity and increase in its acidity. So what does CO2 has to do with it?