Ocean acidification is global warming’s forgotten crisis

Comment: We have the tools to barricade ecosystems against some impacts of warmer, more acidic oceans. But do we have the political will to use them?

A sea snail shell is dissolved over the course of 45 days in seawater adjusted to an ocean chemistry projected for the year 2100. (Photo: Noaa)


Most of us are familiar with the climate change impacts we see and feel in our communities: heatwaves, storms, droughts, floods, and so on.

But a UN meeting this week about climate change and oceans reminds us a related crisis is unfolding largely away public attention: the one-two punch of ocean warming and acidification.

With record temperatures sweeping over continents year after year, it is easy to overlook that the ocean has absorbed some 90% of the heat trapped by the carbon dioxide dumped into the atmosphere since the industrial revolution; and how much of that CO2 has dissolved into seawater as carbonic acid, altering its basic chemistry.

The UN meeting follows on the heels of a new secretary general report that investigates the impacts of these changes and the findings are concerning, to say the least.

The report describes record ocean temperatures pushing fish species toward cooler latitudes and out of reach of artisanal fishers; it documents widespread coral bleaching across the tropical belt and how most reefs could enter a state of permanent decline by 2040; it shows how ocean acidification has damaged a range of calcifying marine life, such as corals and shellfish; and it raises fears that the cumulative effects of the impacts are degrading phytoplankton, zooplankton, and krill, the foundation of the ocean’s food chain.

Estimated change in annual mean sea surface pH between the pre-industrial period (1700s) and the present day (1990s). (Source: Global Ocean Data Analysis Project)

Perhaps most ominously, it warns that the ocean system could be reaching the limits of its ability to store all that excess carbon and heat released by human activities.

The timing of the meeting and report are not accidental. On 5-6 June the UN will host the first ever Oceans Conference, which will focus on accelerating the implementation of Sustainable Development Goal targets designed to restore and conserve marine environments.

One of the targets calls on the international community to cut emissions and address the impacts of ocean acidification.

But even under the best-case scenario global emissions are unlikely to peak before midcentury. That means in the short-term we must take action locally to help build resilience in our fisheries, coral reefs, and coastal ecosystems and give them a chance to adapt to the unprecedented changes.

Pacific islands are already leading the world in these efforts. In just the past few years, Palau, Kiribati, Fiji, and others have created or expanded marine protected areas – zones that prohibit activities known to damage or slow an ecosystem’s recovery.

We also manage the parties to the Nauru Agreement, the world’s largest sustainable purse seine tuna fishery, with a combination of the latest science and strict controls to prevent overfishing and harm to sharks, sea turtles and birds. The approach has led to an increase in the value of the tuna harvest and can serve as a model for fisheries management elsewhere in the Pacific and around the world.

Of course, much more needs to be done. A good start would be for the international community to provide the means of implementation needed to establish more MPAs and support ecosystem-based approaches to marine governance that have proven so successful in the Pacific and elsewhere. The private sector also has a role to play in developing new partnerships and sources of finance to support these goals.

The reality is we possess many of the tools we need to take care of our fish, coral reefs and coastal habitats. But, as with climate change, we lack the political motivation to deploy the solutions as fast and broadly as required. For now, the most important step we can take might be to encourage our leaders to attend the Oceans Conference, listen to what is happening to our oceans, and take action before its too late.

Ambassador Marlene Moses is Nauru’s permanent representative to the UN and chair of the Pacific Small Island Developing States 

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