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Preparing for ocean acidification, a silent killer of climate change

A groundbreaking study published today in the journal Environmental Research Letters presents an innovative framework for governments worldwide to assess their preparedness for one of the most critical threats to marine ecosystems: ocean acidification. The research, conducted by an international team of scientists from over a dozen institutions, including the California Academy of Sciences, aims to guide future policies addressing the issue.

“Ocean acidification is one of climate change’s silent killers,” said Dr. Rebecca Albright, founder of the Coral Regeneration Lab (CoRL). “While not as high-profile as threats like coral bleaching, ocean acidification will cause widespread destruction of marine environments by the end of this decade if we don’t take urgent action.”

Ocean acidification is a process that occurs when the pH of seawater decreases due to the absorption of carbon dioxide (CO2) from the atmosphere. As humans release more CO2 through activities such as burning fossil fuels, deforestation, and industrial processes, a significant portion of this excess CO2 dissolves into the oceans.

When CO2 dissolves in seawater, it forms carbonic acid, which then dissociates into bicarbonate ions and hydrogen ions. This increase in hydrogen ions leads to a reduction in pH, making the ocean water more acidic. The process also reduces the availability of carbonate ions, which are essential building blocks for many marine organisms, such as corals, shellfish, and some types of plankton, to form their shells and skeletons.

Ocean acidification can have severe consequences for marine ecosystems, as it negatively affects the growth, reproduction, and survival of many marine species. It can also disrupt food webs and impact the overall health and biodiversity of ocean habitats. Moreover, ocean acidification has socioeconomic implications, as it threatens the livelihoods of communities that depend on marine resources for food, tourism, and other economic activities.

Albright and her team sought to determine what actions governments should take to develop comprehensive plans to protect both the environment and society from ocean acidification. The researchers identified six aspects of effective ocean acidification policy, each with specific indicators that policymaking bodies, from local governments to federal agencies, can use to evaluate and guide their policies.

The six aspects of effective policy include: climate protection measures, ocean acidification literacy, area-based management, research and development, adaptive capacity of dependent sectors, and policy coherence. These factors encompass considerations such as greenhouse gas emissions reduction, public awareness, resilience in marine protected areas, investment in research, understanding of impacts on political and socioeconomic sectors, and consistency with evidence-based, science-backed efforts to address climate change and ocean acidification.

As a case study, the researchers applied the framework to evaluate Australia’s preparedness for ocean acidification. The country, home to the world’s largest system of coral reefs, supports the livelihoods of over a billion people but is uniquely vulnerable to acidification. 

The experts found that although Australia possesses a deep understanding of the adaptive capacity of vulnerable socioeconomic sectors and management strategies explicitly addressing ocean acidification, it lacks policy coherence and broader climate protection measures, which may hinder its ability to reduce greenhouse gas emissions, the primary contributor to ocean acidification.

“Ocean acidification is not an isolated issue, but rather one that is closely linked to other anthropogenic hazards – in Australia and elsewhere – such as warming, sea level rise, oxygen loss, and eutrophication,” said Dr. Ove Hoegh-Guldberg from the University of Queensland. “Therefore, any policy designed to address ocean acidification either locally or globally must consider the many interconnected factors and their impacts on both ecosystems and society.”

The researchers believe that their framework will help countries establish a baseline to assess their preparedness for ocean acidification, enabling scientists, conservationists, and governing bodies at all levels to identify areas for investment or collaboration to better protect their environments and societies.

“After governments self-assess their readiness for ocean acidification, they’ll have a better sense of where gaps may exist,” said Dr. Sarah Cooley, director of Climate Science at the Ocean Conservancy. “This self-test will help governments focus future efforts to make sure they are emphasizing the most essential areas for them and can take the necessary steps to address the salient threats from acidification.”


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