World leaders gathered to discuss the current biodiversity crisis at COP16 in Colombia this week are being urged to focus more attention on one of the largest—yet so far particularly neglected—contributors to the eventual collapse of the marine environment: ocean acidification.
Scientists have argued that despite its « critical threat » to ocean ecosystems, awareness of the severity of ocean acidification and its role (both past and ongoing) in exacerbating the catastrophic levels of biodiversity loss observed over the last century remains « woefully low. »
In their appeal to leaders from around the world, scientists highlighted that to date, only 13 out of 195 countries have developed national ocean acidification plans, suggesting that the « clock is now ticking » to address a phenomenon that is « already unraveling marine life, food chains, and entire economies. »
This appeal comes in the wake of a recent report from the Back to Blue Initiative, which revealed the extent and impact of ocean acidification.
Ocean acidification occurs when excess carbon dioxide dissolves into seawater, lowering its pH. Research has indicated that this subtle shift in ocean chemistry disrupts the « delicate balance » upon which marine species depend.
“With rising acidity, these once vibrant ecosystems are now slowly disintegrating,” said Professor Steve Widdicombe, director of science at Plymouth Marine Laboratory and contributor to the report.
“And the effects don’t stop there—species of shellfish, coral, and plankton are struggling to survive in these altered conditions, threatening the base of marine food chains and harming coastal communities that rely on fishing.”
Global biodiversity is in an accelerated state of decline. An estimated 28% of the world’s animal and plant species are currently under threat of extinction, according to the International Union for Conservation of Nature (IUCN). This figure has steadily increased each year since the mid-1990s.
The main causes of biodiversity loss today are linked to human activity, including the expansion of agriculture and deforestation on land, as well as overfishing and pollution in coastal waters and the open ocean. A common driver, both on land and in water, is climate change caused by the unrelenting growth of CO2 emissions since the Industrial Age.
The impact of climate change on coral reef systems is well-documented. Between 1957 and 2007, there was approximately a 50% decline in the world’s coral reef cover. A direct consequence of that loss has been a reduced population of coral reef fish.
However, less well-documented, argues the Back to Blue Initiative paper, are declines in marine species critical to ocean food chains, such as coccolithophores—a type of phytoplankton at the base of the food chain.
It is almost certain that a major contributor to the decline of such species is ocean acidification—a direct result of increased carbon dioxide emissions from burning fossil fuels, power generation, transportation, and other human activities.
The ocean absorbs between 20% and 30% of the carbon released into the atmosphere each year, a process that has proven critical in mitigating global warming. But as more carbon is released into the atmosphere, the ocean is unable to process it quickly enough.
When oceans have excess carbon, this usually leads to a lower pH and higher acidity.
“It is, however, difficult to provide sufficient data to link ocean acidification to biodiversity loss,” said Professor Widdicombe. “And without that data, policymakers feel less urgency to address it. The causality, although acknowledged by scientists, needs clearer, irrefutable documentation to generate the global urgency needed for more policy action.”
Unlike an issue like plastic pollution, ocean acidification has been labeled “an invisible threat” that is “harder to detect but no less devastating in the long term.”
“As our oceans acidify, fisheries are projected to see declines in key species, threatening food security for millions of people globally,” said Professor Widdicombe. “Coastal economies that depend on marine biodiversity will suffer significant losses. These aren’t hypothetical scenarios.”
Ocean acidification is included under the UN’s Sustainable Development Goals, specifically under Goal 14 and its Target 3, which calls on countries to “minimize and address its impacts” through enhanced scientific cooperation “at all levels.” It is also part of the new Global Biodiversity Framework and the Convention on Biological Diversity, under Target 8.
However, the capacity to monitor and study the effects of ocean acidification on marine biodiversity is largely insufficient in many parts of the world.
“Governments in Cali must commit to advancing research that will substantiate the link between ocean acidification and biodiversity decline, accelerating the process of creating actionable plans,” urged Professor Widdicombe.
Among those leading developments in ocean acidification action is the IAEA Marine Environment Laboratories, hosted by the Principality of Monaco, which has this month partnered with the Prince Albert II of Monaco Foundation on ocean acidification and ocean-based solutions to climate change.
Under the new partnership, the IAEA and the Foundation will co-organize training courses and expert meetings to empower countries to study and act on ocean acidification. The partnership will also organize events to raise awareness and elevate the profile of new research on ocean acidification among policymakers and other stakeholders at key ocean gatherings, including the United Nations Ocean Conference in June 2025.
“Ocean acidification is a global problem, but how the effects play out depends on local factors,” said Olivier Wenden, CEO and vice president of the Prince Albert II of Monaco Foundation. “Ocean acidification will hit harder in many regions of the world, which do not necessarily have the capacity to monitor and adapt. We are thrilled to be teaming up with the IAEA Marine Environment Laboratories to help bring knowledge and capacity to study ocean acidification to scientists across the globe.”
The partnership echoes the sentiments expressed by Plymouth Marine Lab’s Professor Widdicombe, who stated: “Research isn’t just about gathering data—it’s about creating a sense of urgency. Clear evidence of the damage ocean acidification is causing will force governments to make it an integral part of national biodiversity legislation.
“There’s no more time to waste. Our oceans are in crisis, and without intervention, we may soon pass the point of no return.
Source: oceanographicmagazine
