Ocean acidification is a very real environmental threat. But what’s the science behind how it works?
Oysters have been farmed in the US Pacific Northwest of the United States for thousands of years. A source of local pride, and a tenet of regional folklore, their history has made them a source of regional pride. Native American mythology, for instance, tells of man being born from an oyster, and European settlers understood them to be a gift from God. This reverence has survived, and to this day the creatures exist regionally as cultural and economic touchstones.
However, in 2007, oyster farmers in Washington State and Oregon began to notice large numbers of their stocks mysteriously disappearing, and oyster seeds dying at an unprecedented rate. Seed production in the Northwest dropped by 80% between 2005 and 2009, a shift that devastated local economies and livelihoods. The culprit was a newly discovered phenomenon – often dubbed as ‘climate change’s evil twin’ – called ocean acidification.
Ocean acidification is the reduction in the pH (and therefore ‘acidification’) of the oceans due their absorption of carbon dioxide (CO2) from the atmosphere. This is largely the product of human activity. Since the industrial revolution, human action, such as burning fossil fuels and using land have released 2.3 trillion tonnes of CO2 into the atmosphere. Our oceans are bearing the brunt of this, absorbing one third of all anthropogenic carbon emissions, the equivalent of over 500 billion Volkswagen Beetles dumped into the sea. This uptake has raised the ocean’s acidity by 30%, changing the pH from 8.2 to 8.1; a shift that has carried extreme consequences for marine life.
So, how are these changes manifesting? The most impactful effect has been the reduction of carbonate minerals (minerals containing carbonate ions e.g. aragonite) in the oceans. Without these ions, sea creatures are unable to effectively construct their shells, rendering them brittle and stunting their growth. The effect of this is concentric. Responsible for filtering and cleaning the surrounding water, and providing other organisms with habitat and food, the effect of their mortality is not contained, and has a knock-on effect on marine eco-systems more broadly. Other ocean habitats are endangered by the acidification too. Coral reefs, for instance, struggle with skeleton growth, and stop growing altogether at a pH of below 7.8.
The effect, then, extends beyond the oyster. As oceans continue to acidify worldwide, fishing industries will continue to collapse, creating a loss of income and dietary protein that will be felt around the globe; the United Nations estimates that the industry supports the livelihoods of 10-12% of the world.
Coupled with temperature increase and oxygen loss, the oceans are facing what The Guardian calls a “triple threat” which is devastating marine ecosystems. As it acidifies, the ocean loses its efficacy as a carbon sink, meaning that it can no longer absorb the gases that contribute to the greenhouse effect and global heating. The effect is one of accumulation.
Frighteningly, this effect is reaching a tipping point. A recent report by the Potsdam Institute for Climate Impact Research revealed that we are nearing an irreversible threshold for ocean acidification, which, if broached, would be the seventh of the nine climate thresholds that are required for Earth to support life. It’s sobering news, to say the least.
However, not all hope is lost. While the effects of ocean acidification are most likely irreversible, the rate of change could be slowed down. Scientists believe that cutting down on fossil fuels emissions could go a long way in preserving a rapidly diminishing marine ecosystem. According to the IPCC (Intergovernmental Panel on Climate Change), a serious reduction in emissions could spare up to 30% of coral reefs from extinction.
And while the biggest emitters may be major fossil fuel companies, we as individuals can still make a difference. By cutting down our individual carbon emissions (reducing meat consumption, for instance, can reduce our carbon footprint by up to 30%) we can partake in the conservation of what is a fast dying, yet incredibly important, aspect of our ecosystem. Research suggests that we have five years to make a change. The time to act is now.
Julia MCauley, The Glasglow Guardian, 26 December 2024. Article.
