Fact Sheet

Ocean Acidification (OA)



NCEL Point of Contact

Dylan McDowell
Executive Director



Ocean acidification (OA) is the name for the process of the oceans becoming more acidic due to increased levels of carbon dioxide in the atmosphere. This change threatens ocean ecosystems, the food chain and the livelihood of coastal residents. As the ocean absorbs carbon dioxide, it reacts with water molecules to form carbonic acid, thereby increasing the overall acidity. This puts commercially and culturally important species such as lobsters, clams and oysters at risk. More information is needed about the extent of these changes in specific regions and how to best mitigate those effects.

Key Points

Key Point 1

The ocean absorbs 25-30 percent of carbon dioxide emissions from the atmosphere, roughly 22 million tons per day. (NOAA)

Key Point 2

The oceans are acidifying at a rate 100 times faster than any time in the last 200,000 years, and perhaps all of Earth’s history, according to a 2012 study. (Science)

Key Point 3

Fishermen and the aquaculture industry will lose jobs and profits due to OA. A 2009 study found that mollusk—shelled animals like oysters—sales could drop between $75 and $187 million annually due to acidic ocean conditions. (Environmental Research Letters)


  • In 2019, Maine established the Science and Policy Advisory Council to assess the impact of climate change on Maine’s marine species. This council works to strengthen scientific monitoring and research regarding the potential effects of climate change on the state’s marine ecosystems. The full text can be found here.  
  • Maine and Maryland task forces have completed reviews, and legislators in those states are now looking to implement recommendations. Massachusetts, Rhode Island, New Hampshire and Oregon have introduced similar bills to establish an OA task force. 
  • Oregon introduced S.B.260 (2019), which appropriates money from the Oregon Science Trust and the State Department of Fish and Wildlife and Higher Education Coordinating Commission to analyze ocean chemistry.


NCEL Resources

Success Story

NCEL Helps Spread Ocean Acidification Model from Washington

October 26, 2019

Online Resources

Pacific Oysters Gain from Ocean Acidification Data - NOAA

OA observations benefits the $111 million West Coast shellfish industry.

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Ocean Acidification Affects Northeastern US Coasts More - LiveScience

Coastal regions around the United States respond differently to ocean acidification, a large-scale study finds.

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As Pacific acidifies, ‘sea butterflies’ are quickly losing their shells - PBS

Scientists have known for some time that shells of the tiniest sea life have been dissolving due to an increasingly polluted ocean.

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