What Is Ocean Acidification?

Let’s begin this topic by exploring the chemistry behind this phenomenon.

Ocean acidification is the long-term decrease in pH levels of the ocean. This phenomenon is primarily caused by the ocean’s absorption of carbon dioxide (CO2) from the atmosphere. Over the past 200 years, since the Industrial Revolution, humans have been releasing exponentially more CO2 into the air. Burning of fossil fuels such as gas, coal, and oil has added 365 million tons of CO2 to the atmosphere, and another 180 billion tons from deforestation.

The ocean serves as the world’s largest carbon sink, absorbing approximately 30% of the world’s CO2, and this absorption rate continues to increase as CO2 emissions rise. Monitoring has shown that the ocean absorbs millions of tons of CO2 every year. 

When carbon dioxide is absorbed by the ocean, it dissolves into the water. This dissolution leads to the formation of three kinds of carbon: bicarbonate ions, carbonate ions, and carbonic acid. Along with this, hydrogen ions are also produced. The increased concentration of hydrogen and carbonate ions and acids is what leads to a more acidic ocean.

It’s important to note that while ocean acidification leads to a decrease in pH, the term “acidification” can be misleading. The ocean remains more alkaline than acidic, even as its pH decreases, it is still more alkaline than tap water.