Why you should care
If change doesn’t happen soon, ocean acidification will permanently devastate ecosystems, human well-being and economies around the world.
Scientists describe ocean acidification as the “evil twin” of climate change. Humanity’s carbon habit is fundamentally altering not only the atmosphere but also the chemical balance of the ocean, with vast and serious impacts documented in an expert report released last week to coincide with the U.N.’s annual climate talks in Warsaw.
Number of metric tons of CO2 the ocean absorbs every day (IGBP Report)
The ocean’s ecosystem is being drastically altered, perhaps irrevocably, as carbon dioxide reacts with water to form carbonic acid. Imagine seawater becoming less like water and more like lemon juice, and you begin to understand the threat to hundreds of thousands of ocean species. The transformation of the seas will also impact landlubbers. Fisheries face huge losses, tourism will suffer, shoreline protection will be undermined and the effects of climate change will be exacerbated.
First, some science
Life on Earth depends on complex biogeochemical cycles, and the oceans are an essential element of those processes. Oceans have slowed the pace of climate change by acting as a “carbon sink,” along with other sinks on land like rain forests. Without this interaction, the globe would be at an even higher atmospheric CO2 than the alarming milestone of 400 parts per million hit this year (we’d be 76 ppm higher, by one estimate). As the oceans lose their capacity to absorb additional CO2, there is a risk of climate “threshold effects” — the radical and unpredictable changes that occur when a critical line is crossed.
The pH scale ranges from 0 to 14. Pure water has a pH of 7. Why does it matter that ocean pH has dropped by 0.11? Consider that a 0.1 change in your blood’s pH would result in seizures, heart arrhythmia, or even coma. Marine organisms are soaking in that change. — Learn more at NOAA.
Despite the scale of the threat, ocean acidification is a largely invisible catastrophe. It gets hardly any media coverage and is rarely addressed by policy makers. The U.N. officially recognized ocean acidification as an ecological and economic threat at its Rio+20 Sustainable Development Conference in 2012. However, there are no international treaties or mechanisms in place to deal with the issue.
The ocean’s pH level is lower than it has been for 50 million years, meaning it’s more acidic than ever. To put that in context, in the coming decades Earth will experience ocean conditions that have not existed since the time of the dinosaurs — but which humans managed to create in less than 200 years. Since the Industrial Revolution, ocean acidity has increased by over a quarter and, if the current rate of acidification persists, by 2100 there will be a 100-percent increase.
Increase in the ocean’s acidity since the Industrial Revolution (IGBP Report)
Unsurprisingly, sea life is the first casualty of ocean acidification. Many ocean animals depend on their calcium carbonate shells for survival, but acidic conditions dissolve shells and prevent them from being rebuilt. The deterioration of the coral reefs is a prime example of this phenomenon. Coral cannot maintain its calcium carbonate shell in acidic conditions; it becomes bleached and ultimately dissolves. One in four of the ocean’s species lives in and depends on coral reefs, meaning they face extinction as the coral disappears.
The expected lifespan of the coral reefs (Acid Test)
The number of ocean species living in the coral reefs
Other shelled sea creatures are similarly vulnerable. The availability of luxury seafood, such as lobster, oysters and crab will decline. Acidification will also diminish the food supply of seals, whales, sharks and other sea creatures as pteropod, or sea snail, populations shrink. Pteropods are small, shelled sea creatures that exist in huge numbers and form the foundation of many ocean food networks. Ocean species can only tolerate so much before extinction comes knocking: If pteropod numbers drop, it will disrupt the entire food chain — including humans.
Estimated economic cost of the destruction of coral reefs (Nature)
Around the world, 540 million people rely on fisheries for their livelihoods. The decline of fish stocks, which have already been depleted by overfishing, will have a resounding economic impact —the depletion of mollusks alone could cost the fishing industry $130 billion by 2100. Furthermore, a billion people, mostly in developing countries, depend on fish as their primary source of protein. Their economies are suffering the effects of ocean acidification, but so will their diets.
Revving Up Climate Change
While these groups are the most severely affected, no one will escape the impacts of ocean acidification. At present, the ocean absorbs a quarter to a half of the carbon dioxide we emit as well as excess atmospheric heat, which moderates the effects of climate change. Acidification and ocean warming restrict the seas’ capacity to absorb CO2 , which many suspect will accelerate the pace of climate change.
Amount of ocean diversity that may be lost by the end of the century (BBC)
The only way to meaningfully reduce the rate of ocean acidification is by dramatic control of carbon emissions. Establishing marine protection areas, reducing pollution and sustainably replenishing fish stocks will all increase the ocean’s resilience, but these are supporting policies. They are not solutions. Ocean acidification and climate change have the same cause, so they also have the same solutions: cutting fossil fuel consumption, slowing forest loss and increasing the accessibility and usage of renewable energy.
To paraphrase Seinfeld: The sea is angry, like an old man trying to send back soup in a deli. If we don’t address the acidification crisis, we will feel its wrath.