Oceans could be 150% more acidic by 2100
Most of the cliffs that you see bordering the south of England and the Normandy coast were built by deposition of sediments of shellfish that have grown in steady conditions of carbonate and CO2 available in the oceans at geological scale. It is supposed that this should still continue, as carbon is trapped in the shells of mollusks in a permanent and stable manner, but we suspect that the future will be different.
Rising levels of atmospheric carbon dioxide (CO<sub>2</sub>) are causing the ocean to acidify at rates not seen for the last 20 million years. Atmospheric carbon dioxide is absorbed by the ocean (at least half of all emissions pass into the seas) increasing the acidity and resulting in “Ocean Acidification”.
A more acid ocean affects marine plants and animals by causing calcium carbonate, the stuff of shells and skeletons and the basis of much of the ocean’s phytoplankton, to dissolve, thus, probably, greatly affecting marine food webs, causing extinction of species vital to the health and productivity of the earth. Business as usual scenarios for CO<sub>2</sub> emissions could make the ocean up to 150% more acidic by 2100. Regrettably these problems are not yet recognised outside the oceanographic research community.
The impacts of ocean acidification on marine life, and ultimately the socio-economic effects, are potentially dramatic. Coastal communities and small island developing states (SIDS), which rely on marine-based ecosystem services for a significant portion of their livelihoods, will be the first to feel the impacts of increased ocean acidification.
The global decrease of coastal marine resources and decline in marine biodiversity will impact countries dependent on coastal fishing, fish-processing industries and tourism causing economic hardship as well as destabilising food security for the 1 billion people who depend on fisheries for most of their protein diet.
Ocean issues are global and affect all Nations. Many developing nations and particularly SIDS still lack the scientific and management technologies and knowledge to effectively manage their marine areas. Raising awareness of the impact of ocean acidification on SIDS and building their capacity to respond to the challenge of impacted marine ecosystems is a top priority of the Intergovernmental Oceanographic Commission of UNESCO (UNESCO-IOC). In an effort to increase awareness of this critical issue, the UNESCO-IOC has convened a series of symposia on “The Ocean in a High-CO<sub>2</sub> World” and published documents describing the impact and options for remediation of the Ocean Acidification problem.
Because of its potential impacts on the marine food chain, biodiversity, food security and livelihoods of coastal community, we believe Ocean Acidification needs to be recognized as a critical ocean issue and acted upon by the international community in the context of the Rio+20 Conference discussions on sustainable development.
Through the report “A Blueprint for Ocean and Coastal Sustainability” led by IOC/UNESCO, and other UN agencies, a proposal to implement a number of urgent actions to mitigate and adapt to ocean acidification has been tabled for consideration by UN delegates negotiating the Rio outcome document.
One of these actions is to launch a global inter-disciplinary program on ocean acidification risk assessment, which would assist countries in formulating mitigation responses. This will also identify regions most at risk of impact from ocean acidification and forecast ‘point of no return’ tipping points where increasing acidification could lead to marine ecosystem collapse. In addition, a call is made to the United Nations Framework Convention on Climate Change negotiations to include atmospheric carbon dioxide impacts on ocean chemistry and ecosystems in their deliberations.
As we are entering the negotiation phase of the declaration that will be adopted at Rio+20, there are encouraging signals that ocean acidification will be considered. In the zero –draft declaration released on 10 January by the UN, the proposals put forward in the Blueprint Report have been included.
IOC will however continue in the coming weeks to ensure that these issues remain high on the international agenda. Rio+20 presents a unique possibility to bring this critical planetary issue to the attention of the public and global decision makers – it is essential that we take advantage of this timely opportunity.
By Wendy Watson-Wright for RTCC.org (Full article and video).
Wendy Watson-Wright is Assistant Director General and Executive Secretary of the Intergovernmental Oceanographic Commission of the United Nations Educational, Scientific and Cultural Organization.
This article is part of a series written in collaboration with RTCC.org; other articles include:
- UNESCO: Vital fate of oceans on Rio+20 agenda
- Coastal erosion major threat to West Africa
- Micro-plastic ‘soup’: the oceans’ hidden threat
- 'Coral reefs could recover, but action is needed, say experts'