Ocean acidification is one of the less talked about impacts of global warming. Our collective consciousness has somewhat moved past conjuring images of polar bears on melting ice caps when we think of climate change, and now we talk about natural disasters felt closer to home — drought, floods, fires, rising sea level, storms. Ocean acidification is rarely brought up in typical media — so what is it, and why does it matter?
Our oceans, which cover ~70% of the Earth’s surface, are a major carbon sink, absorbing ~30% of the carbon dioxide released into the atmosphere. As carbon dioxide is absorbed into the oceans, it combines with water to form carbonic acid, which then breaks down to increase the concentration of hydrogen ions in the seawater, raising its acidity. According to the National Ocean and Atmospheric Association (NOAA), since the industrial revolution, our ocean waters have had a thirty percent increase in acidity.
As the oceans become more acidic, ocean species such as oysters, clams, and corals, find it more difficult to build their hard shells and skeletons. Existing shells and coral reefs become weaker and can dissolve in a more acidic environment, leaving these species vulnerable.
The health of ocean ecosystems is also threatened by organisms that thrive in more acidic waters — in particular algae. As the acidity of ocean waters increases, algae blooms, including toxic algae blooms, become more common. Toxins from algae blooms have been documented to kill seabirds and seals, and can poison humans who consume contaminated seafood.
The threat to ocean species and disruption of the ocean environment is problematic in itself. However, to put it into human terms, the impact of ocean acidification can lead to economic losses for communities dependent on fisheries and ocean tourism. The Union of Concerned Scientists estimates that by the end of the century, the shellfish industry could experience a cumulative loss of $230 million due to decreased supplies of clams, scallops and other consumer foods. They also estimate that acidification paired with ocean warming could lead to $140 billion in losses from recreation decline, with the US coral reef industry declining in value by more than 90%.
To combat the effects of ocean acidification, some scientists are looking into growing seaweed to help slow the impacts. However, the main solution would be to curb global warming — reduce our use of fossil fuels, and emit less carbon dioxide into the atmosphere. It is yet another motivation for us to fight for a deep decarbonization of our grid and move towards a renewables based economy.
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