Ocean Acidification

Understanding the Threat and Charting a Course for Resilience

Here’s a fun little fact to read in your inbox: since the Industrial Revolution, the pH of surface ocean waters has decreased by approximately 0.1 units, representing a 30% increase in acidity. This may seem like a small change, but it represents a significant shift in ocean chemistry. And this has far-reaching consequences for our marine world.

You might not know this, but as carbon dioxide levels in the atmosphere surge, a significant portion is absorbed by the ocean. Around a third to a half of the CO₂, to be exact. As carbon dioxide dissolves in the ocean, it reacts with seawater to form carbonic acid, lowering the pH levels and making the ocean more acidic. To no one’s surprise, ocean acidification is fuelled by human-induced carbon emissions. Often referred to as the “other CO₂ problem” and the “evil twin” of climate change, this increased acidity disrupts the delicate balance of marine life, particularly threatening the formation and integrity of calcium carbonate structures crucial for many organisms.

The repercussions of ocean acidification are far-reaching and profound.

For marine animals dependent on calcium carbonate - think molluscs, shellfish, and corals - the corrosive effects of acidified waters challenge their ability to build and maintain their protective shells and skeletons. This disrupts food webs, can alter species distributions, and jeopardizes the survival of iconic marine species. Not to mention we’ll see declines in shellfish populations and more frequent coral bleaching events! And while the effects of ocean acidification may be most keenly felt in coastal regions and vulnerable marine habitats, its ramifications extend past our shores.

Ocean acidification poses significant economic and social challenges, particularly for communities that depend on marine resources for food security and livelihoods. Fisheries, aquaculture, and tourism industries may be adversely affected by declines in fish populations, coral reef degradation, and loss of biodiversity, leading to economic losses and social disruption in coastal communities.

So, we know the threat. What can we do?

Well, mitigating ocean acidification requires ambitious emission reductions to curb the flow of carbon dioxide into the atmosphere and slow the pace of climate change. Investments in research and monitoring are essential to deepen our understanding of ocean acidification and its impacts on marine ecosystems, guiding adaptive management strategies and informed decision-making. That’s why initiatives like the United Nations Sustainable Development Goal 14 (Life Below Water) include targets to address ocean acidification and its impacts on marine ecosystems. International agreements, such as the Paris Agreement on climate change, also aim to reduce greenhouse gas emissions and limit global warming.

Acidification is not merely a scientific curiosity or an abstract concept — it is a real thing happening in our oceans right now. Yes, scientists and researchers around the world are studying the effects of ocean acidification on marine ecosystems and developing strategies to mitigate its impacts. However, efforts to reduce carbon emissions, promote sustainable practices, and implement conservation measures are crucial in safeguarding the health and resilience of marine ecosystems. The knowledge that our oceans, the lifeblood of our planet, are undergoing a profound transformation demands a collective response. Our choices today will shape the course of marine ecosystems, ensuring that the beauty of our oceans endure beyond this deadly shadow.

Here’s hoping what’s left of 2024 and 2025 sees those in power take this issue seriously.