COP26: IAEA, UNESCO call for stronger recognition of ocean acidification

Coral bleaching on the Great Barrier Reef, 2017. (Photo: The Ocean Agency/Ocean Image Bank) 

Increasing global capacity for observation of and research in ocean acidification is key to help minimize the impact of climate change on oceans, participants heard at a side event at the global climate change conference.

The IAEA and the Intergovernmental Oceanographic Commission (IOC) of UNESCO invited policymakers and the world’s leading ocean science experts to the event at the 26th United Nations Climate Change Conference (COP26) in Glasgow, United Kingdom, to review how the global community can best address the problem of ocean acidification and its consequences.

As the amount of carbon dioxide (CO2) increases in the atmosphere due to human activity, more CO2 will dissolve in sea water, creating a chemical reaction that makes the oceans more acidic. This impacts plants and animals living in the ocean, which are not used to living under such acidic conditions. Corals and shellfish, for instance, corrode in an increasingly acidic environment. Because oceans absorb a third of human made, or anthropogenic, CO2, the rate at which ocean acidification will increase in the 21st century will be dependent on future CO2 emissions, according to the Intergovernmental Panel on Climate Change (IPCC) Report 2021.

“There can be no healthy planet without a healthy ocean,” said Peter Thomson, UNSG’s Special Envoy for the Ocean in his opening remarks. “The global ocean community has long considered this COP26 to be the most opportune time to stop the accelerating decline of the ocean’s health – a decline that is being scientifically measured by rates of the ocean’s acidification, it’s warming and loss of oxygen and marine habitats.

Systematic adaptation strategies to respond to the consequences of ocean acidification are not yet in place due to fundamental technological and knowledge gaps. To address these knowledge gaps, the international experts, through currently existing mechanisms such as the UN Communities of Ocean Action on Ocean Acidification, the Global Ocean Acidification Observing Network (GOA-ON) and its UN Ocean Decade Programme Ocean Acidification Research for Sustainability (OARS), the IAEA’s Ocean Acidification Coordination Centre (OA-ICC) and partner organizations, work closely to carry out global initiatives and engage scientists, communities, policymakers and the media.

“Minimizing the impacts of ocean acidification does not occur in isolation. Addressing such a complex and spiralling environmental problem requires strategic, international partnerships,” said Jodie Miller of the IAEA’s Department of Nuclear Sciences and Applications. “The IAEA’s OA-ICC serves as an international hub to communicate, promote and facilitate international activities on ocean acidification, working closely with IOC-UNESCO, the Ocean Acidification Alliance, GOA-ON, and many other partners to spread awareness and raise capacities in this area.”

Miller explained that projecting scenarios for the future and developing workable adaptation strategies require data on ocean acidification processes and the capacity of marine ecosystems to handle its consequences. The IAEA’s OA-ICC contributes to these objectives by building capacities of experts worldwide to monitor ocean acidification and develop informed responses.


Alarming acidification with “business as usual”

Carbon dioxide (CO2), which is naturally present in the atmosphere, dissolves into seawater. Water and carbon dioxide combine to form carbonic acid (H2CO3), a weak acid that breaks (or “dissociates”) into hydrogen ions (H+) and bicarbonate ions (HCO3). It has the effect of reducing the availability of carbonate ions (CO32-), as they bond with excess hydrogen, resulting in fewer carbonate ions available for calcifying organisms to build and maintain their shells, skeletons, and other calcium carbonate structures. If the pH gets too low, shells and skeletons can even begin to dissolve. Oceans are slightly alkaline, with a pH of around 8.1 (ranging from 7,8 to 8,5). Since the industrial revolution, the average pH of surface ocean waters has fallen by 0.1 pH units. This might not sound like much, but the pH scale is logarithmic, so this change represents approximately a 30 per cent in acidity. According to UNESCO, business as usual scenarios for CO2 emissions could make the ocean up to 150% more acidic by 2100.

IAEA, 10 November 2021. Full article.

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