Understanding Ocean Acidification

Ocean acidification is one of the most alarming yet somehow overlooked results of rising carbon dioxide levels in our atmosphere. A large portion of carbon dioxide is being absorbed into the ocean, because of the burning of fossil fuels and increased deforestation. According to the National Oceanic and Atmospheric Administration (NOAA), around 30% of global carbon emissions are being taken into the ocean, having many dangerous effects on sea-life and their environment. But how does this uptake of carbon dioxide occur? When carbon dioxide dissolves in the ocean, it reacts with the water molecules to produce carbonic acid. The carbonic acid breaks apart and releases hydrogen ions, and the more hydrogen ions are floating around, the more acidic the water becomes. Since the Industrial Revolution, the average pH of surface water in the ocean has fallen by 0.1 units, which basically means a 30% increase in acidity.

This may not seem like much, however, this change carries great impacts. For starters, many marine species such as oysters, corals, and pteropods (tiny sea snails with wings) rely on carbonate (which comes from carbonic acid) to build their shells and skeletons. As the acidity of their environment increases, carbonate becomes less available which weakens their shells and could even cause them to dissolve. This is unfortunately the reality for all marine organisms that rely on carbonate for their shells or body structures. The NOAA states that pteropod shells placed in predicted future ocean conditions started dissolving within just 45 days. This has very harmful implications for marine biodiversity and all food webs that depend on these creatures.

The European Environment Agency (EEA) reports similar trends worldwide. Seawater pH has dropped from 8.11 in 1985 to 8.04 in 2024, showing an 18% increase in acidity in just 39 years. With these statistics, many people speculate that there will be an even more rapid increase in ocean acidity in the near future. This not only impacts ocean ecology, but it also weakens the global economy. Due to the decrease of animals such as clams and oysters, fisheries lose valuable harvests. This drives up the price of seafood and decreases profit and jobs for fisheries. Another example is seen in coral reefs which support tourism and protect the coastlines in coastal communities. Now, since they are weakened and broken down by the increase in ocean acidity, many communities are vulnerable to storms and losing a major source of income. These consequences have larger implications as they affect food security, international trade, and the lives of millions around the world.