The ecological impacts of ocean acidification on ecosystems are not well understood. Therefore, it is difficult to predict how ocean acidification will impact human communities. Because acidification affects fundamental processes related to the overall structure and function of marine ecosystems, any significant change could have far-reaching consequences for the oceans of the future and the billions of people that depend on marine resources for their food and livelihoods.
Commercial and Recreational Fisheries
As ocean acidification affects the ability of marine organisms to form shells and skeletons, it is likely to decrease the abundance of commercially important shellfish species such as clams, oysters, and sea urchins. This affects the human communities that depend upon these resources for food and/or livelihoods. ref
In addition, acidification is likely to affect marine food webs and lead to major changes in commercial fish stocks. ref Ocean acidification influences the structure and productivity of primary and secondary benthic and planktonic production, which can affect the productivity of fish communities and higher trophic levels. For example, young salmon prey on pteropods, a type of zooplankton that is highly vulnerable to ocean acidification. Additionally, the interaction of acidification with thermal tolerance may affect the temperature-dependent ranges of many fish species.
Decreases in abundance of fishes and changes to marine food webs threaten the protein supply and food security of millions of people, as well as the multi-billion dollar fishing industry.
Coastal Communities and Associated Economies
Ocean acidification will likely impact coastal communities and economies. Coral reefs provide fish habitat, generate billions of dollars in tourism, protect shorelines from erosion and flooding, and provide the foundation for biodiversity. For many communities, new economic development is dependent on coastal tourism. Healthy coral reefs generate tourist dollars and provide coastal protection for infrastructure (such as hotels and resorts).
Increased Impacts of Climate Change
Ocean acidification, along with warming surface waters and changes in ocean mixing, may reduce the ability of the ocean to absorb CO2. This results in more CO2 in the atmosphere. Because CO2 is the primary greenhouse gas contributing to climate change, increased CO2 contributes to increases in global temperatures and associated changes in sea level, storm and precipitation patterns. When the ocean’s ability to absorb CO2 is reduced, humans are likely to feel the impacts of climate change more severely. This reduction also makes it more difficult and more expensive to stabilize atmospheric CO2 concentrations.