Ocean Acidification: A Sea of Problems

When we hear ‘climate change’, the images conjured up all fall along a similar theme: oil pumpers, emissions coming out of an industry factory, ice melting in the Arctic… All well above the water. But what really happens under the sea, and is it really better down where it’s wetter?

The oceans cover over 70 per cent of the earth’s surface and contain 97 per cent of all life on earth. They make up part of the same body – whatever the land emits; the oceans will feel the effects of it. And right now, the ocean is feeling unprecedented levels of greenhouse gas emissions. In the last 250 years, atmospheric concentration of carbon dioxide has sky rocketed from an estimated 280 parts per million to over 294 parts per million, well above the predicted dangerous upper limit of 350 parts per million. The oceans naturally absorb excess carbon in the atmosphere in the form of carbonic acid.  Though this is a benefit in that this extra absorption has largely shielded us from the most dire impacts of our action, the side effect for the oceans is a decrease in pH level, leading to acidification.


Image Courtesy of J. Roff ©2005
Image Courtesy of J. Roff ©2005

What are the consequences of an acidic ocean?

The UK’s chief scientist Sir Mark Walport recently warned that the acidity of the oceans has increased by about 25 per cent since the industrial revolution as a result of increased emissions. He emphasized the growing risks to marine ecosystems, and noted that the current rate of acidification was believed to be unprecedented within the last 65 million years.

The main threats of ocean acidification are to marine food webs. In the process of reacting with seawater to form carbonic acid, there is a large consumption of carbonate ions, an essential component in the formation of calcium carbonate shells, common in many marine organisms like corals, marine plankton, and shellfish. With increased acidification, these shells cannot calcify and form properly, and so many organisms are left vulnerable to weakness. Not only does this weakness affect these organisms, but this problem travels all the way up the food chain. For the billion people, mainly in developing countries, who rely on fish as a main source of protein; ocean acidification is all too real. Moreover, coral reefs, as a hub of ocean habitats and home to thousands of marine organisms, face destruction in inhospitable oceans all over the world if the issue continues unchecked.

The oceans have a finite capacity as a ‘carbon sink:’ scientists worry that the oceans are rapidly approaching an upper limit of absorption. This would mean all excess carbon we emit would go straight into the atmosphere, further worsening the impact of climate change.  Despite the gravity of the issue, and its incredibly wide geographical impact, many of the issues surrounding climate change and the oceans, and in particular ocean acidification, have been marginalized on the climate negotiations.

Why ocean acidification needs more attention

Ocean acidification is one of the most significant impacts of climate change, yet has been rarely discussed at the public level. Perhaps it’s because to the average carbon emitter, the possibility of an acidic ocean doesn’t seem as frightening as the other more menacing threats of sea level rise, or as evocative as cute polar bears with no home. However, ocean acidification threatens to upset the delicate balance within the oceans and affect the lives of everyone who relies on a fish-based diet, and all fishermen who rely on a steady stream of supply from the regenerative ocean.

A recent report showed that ocean acidification has the potential to damage the organs of the Atlantic herring. This fish population reaches from North America all the way to Western Europe and the Baltic sea. This is just one example among hundreds or even thousands of species of fish directly at risk as a result of ocean acidification. This issue can easily be set aside to deal with the more tangible side effects of climate change, but it is essential that we address it now before the oceans’ pH levels decrease any further.

A pricey problem

The potential costs of increased ocean acidification are astronomical. In a recent United Nations report, scientists predicted billions lost in the global economy as a result of loss of yields in the fishing industry, a huge drop in marine tourism and threats to the pharmaceutical industry. The most pressing concern is the immediate threat to food security: fish products make up more than 27 per cent of daily protein intake in Asia, as compared to 7 per cent in North and Central America. Many of the central ‘upwelling’ regions, where cold water packed with nutrients is brought up to the surface and replacing the nutrient-depleted surface water, are under the most pressure from ocean acidification because of the comparative difference in pH levels. Paired with a steadily rising population, food security stands to be one of the most negative human implications of ocean acidification.

Many of the current regulatory frameworks on controlling carbon levels in the atmosphere have been focused on land-based impacts. Most of the Kyoto Protocol sought to address on-land issues and impacts, such as sustainable agriculture, limiting emissions in the transport sector, and waste management on land, but has not shed much light on the long-term impacts for the oceans. Though there is scientific consensus on the issue, the threat of ocean acidification should be more prevalent in legislative discourse to inform the decisions made by states.

Marine activists are putting pressure on governments all over the world to implement carbon-cutting policies to make a concrete change in the global acidity level. As dead zones across the oceans are multiplying at an unprecedented rate, environmentalists are desperate for changes in carbon habits across both developed and developing countries. The oceans are at threat, and all those who depend directly on marine life to sustain their livelihoods will absorb the brunt of the consequences in the first instance.

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