Every year the ocean absorbs at least a quarter of the carbon dioxide (CO2) released to the atmosphere from burning of fossil fuels, cement production and land use change. This is driving ocean acidification.

In 2019 OSPAR established an Intersessional Correspondence Group on ocean acidification (ICG-OA). The ICG works to its Terms of Reference with the remit to lead OSPAR's monitoring and assessment for ocean acidification.

To acknowledge the urgency of this issue, OSPAR Contracting Parties added climate change and ocean acidification to its North-East Atlantic Environment Strategy 2030.

In 2023 OSPAR became an affiliate member of the Ocean Acidification Alliance.

OSPAR's strategic objectives to address ocean acidification

To achieve seas resilient to the impacts of climate change and ocean acidification we will:

Strategic objective 10. Raise awareness of climate change and ocean acidification by monitoring, analysing and communicating their effects;

Strategic objective 11. Facilitate adaptation to the impacts of climate change and ocean acidification by considering additional pressures when developing programmes, actions and measures;

and Strategic objective 12. Mitigate climate change and ocean acidification by contributing to global efforts, including by safeguarding the marine environment’s role as a natural carbon store.

OCEAN ACIDIFICATION IN THE NORTH-EAST ATLANTIC

ICG-OA, co-convened by Ireland and the Netherlands, worked to produce OSPAR's first ever assessment on ocean acidification for OSPAR's Quality Status Report 2023.

Key findings from the assessment

  1. Ocean acidification has been observed in all OSPAR Regions during the past decades. It is projected to keep occurring and even accelerate under the higher carbon dioxide (CO2) emission scenarios.
  2. The rate at which ocean acidification occurs varies geographically and throughout the water column. This variability is particularly evident in coastal environments due to the complex interactions of local physical, chemical and biological processes.
  3. Ocean acidification is a major threat to marine species and ecosystems, with direct consequences to ecosystem services. Studies on biological impacts have indicated that there will be clear changes in organisms’ structure, distribution, and ability to function as a result of ocean acidification effects.
  4. Threatened and / or declining species and habitats, for example cold water coral reefs Lophelia pertusa, are particularly vulnerable to changing environmental conditions, including ocean acidification, and evidence suggests that some commercially important species may also be negatively impacted by these effects.
  5. Ocean acidification effects interact with other pressures from environmental change and ecological interactions. The ability of species to adapt to ocean acidification will depend on the rate of environmental change, evolutionary processes and for most species, the present standing genetic variation.
  6. Our understanding of trends, variability, drivers, and ecological impact of ocean acidification needs to improve. This requires better harmonised and tailored monitoring and data integration, further integration of observations and model products, and an ongoing multi-strand research effort to better predict impacts.
  7. Climate change mitigation and adaptation responses are in many cases also effective against ocean acidification, but some proposed responses may also exacerbate ocean acidification and its impacts.
General trends in key community and ecosystem properties and processes in response to ocean acidification in seagrass meadows, coral reefs, other carbonate reef ecosystems, and pelagic food webs.

ICG-OA summary records

The summary records of the meetings of ICG-OA are published on the OSPAR website

Joint OSPAR/ICES Study Group on Ocean Acidification (SGOA)

OSPAR works with partner organisations such as the International Council for Exploration of the Sea (ICES), the Intergovernmental Oceanographic Commission (IOC) and the Arctic Council to enhance the knowledge on these issues. The Joint OSPAR/ICES Study Group on Ocean Acidification (SGOA) was formed in 2012, chaired by Evin McGovern (Ireland) and Mark Benfield (USA). In total 33 scientists representing 12 countries participated in SGOA.

Final Report to OSPAR of the Joint OSPAR/ICES Ocean Acidification Study Group (SGOA)