Ocean Acidification

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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.

The acidic conditions created by CO2 emissions are harming fisheries, aquaculture farms, coastal recreation and diversity in the ocean. Animals like oysters and clams use a substance called calcium carbonate to build their shells. Acidic water erodes that calcium carbonate and makes the organisms fragile, much like osteoporosis in a human. Even worse, the acidity could completely eliminate animals like the pteropod—a type of sea snail—that serve as a key food source for small fish, which in turn feed commercial fish like salmon and tuna. Investing in long-term research will help determine specific impacts of OA and will lead to the development of effective management and mitigation tactics to preserve our economies and ecosystems.

Key Points

1) As the ocean absorbs carbon dioxide, it reacts with water molecules to form carbonic acid, thereby increasing the overall acidity.

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. 

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

4) 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.

NCEL’s Ocean Acidification Factsheet



  • In 2012, Washington State created the Blue Ribbon Panel to review OA research and issue recommendations. The Marine Resource Advisory Council was subsequently created to establish a coordinated response to OA and engage in public outreach. More information, including bill text, is available here.
  • Maine and Maryland task forces have completed reviews, and legislators in those states are now looking to implement recommendations. 
  • In 2016, California (AB.2139), New Hampshire (SB.375), New York (A.10264), and Rhode Island (H. 8223) enacted legislation to study the impacts ocean acidification on their states’ economies. California also enacted a bill to look at OA mitigation through a blue carbon program (SB.1363).  New Hampshire’s bill includes this provision as well.


Science and Reports

This report highlights major findings and recommendations that can be taken now to address ocean acidificaition and hypoxia. The panel included stakeholders from British Columbia, California, Oregon and Washington. The full report is available here

This report outlines the impacts of ocean acidification on Washington State and provides recommendations for action. These recommendations later established the Washington Marine Resources Advisory Council. The full Blue Ribbon Panel report is available here

This commission, created by the state legislature, analyzed existing and potential effects on species that are commercially harvested and grown along the Maine coast. The full report is available here

This report details the impact of ocean acidification on state waters and is directed at the Governor and State General Assembly. The full report is available here.  


Download the NCEL Fact Sheet with key points and links to legislation here

TOF has compiled an extensive list of resources including news articles, studies, presentations, books and more to learn more about ocean acidification. The resource page is available here

PMEL conducts extensive research on ocean acidification. This website highlights key research and provides excellent graphs and charts to demonstrate the impacts of chemical changes in the ocean. The full website is available here

NOAA created a one-page fact sheet detailing the ocean chemistry behind ocean acidification, and what the main concerns are from this chemical change. The fact sheet is available here.  

This article provides a collection of resources for understanding the drivers of ocean acidification, and details the legal authority states can use to address the issue. The full collection of selected works is available here

The United Nations Environment Programme presents detailed examples how fisheries and aquaculture will be hurt by rising acidity levels in the ocean. The full report is available here.  


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