Ocean Acidification (OA) is threatening the well-being and livelihoods of Pacific Island people. The ocean absorbs about 30% of the carbon dioxide (CO2) that is released in the atmosphere, leading to more carbonic acid being formed, increasing ocean acidity. The reaction of CO2 with water forms carbonic acid, which increases acidity of seawater in a process known as ocean acidification. 

The increasing seawater acidity is reducing the amount of free carbonate in seawater making it more difficult for coral, shellfish, and other calcifying organisms to build and maintain their shells and skeletons. Surface seawater is already 30% more acidic than it was 50 years ago. Globally, seawater pH has already decreased by about 0.1 pH units and is expected to decrease an additional 0.3 pH units by 2100.  


With their vast marine area and large number of reef dependent communities, Pacific Island Countries and Territories are especially vulnerable to ocean acidification. There is increasing evidence that coral in the South Pacific is already experiencing decreased calcification due to ocean acidification. 

PCCOS, through the Pacific Islands Centre for Ocean Acidification (PIOAC) (link to project page) is supporting stakeholders with ocean acidification monitoring programmes.