By the end of the century, 75% of seawater will be corrosive to most corals and shellfish.
Ocean acidification is often called climate change’s evil twin, and with good reason. Both are the dangerous products of our excessive CO2 emissions, and both are causing significant environmental damage on a global scale.
But then why, you may wonder, does climate change seem to be the one getting all the attention? If ocean acidification is really just as bad, why isn’t the public freaking out about it more? Well, that’s because ocean acidification is more of a silent killer— difficult for us to see or feel because it works almost exclusively underwater.
The ocean is — by far — the largest carbon sink on Earth. Over 30% of the CO2 released into the atmosphere is absorbed by our ocean. That translates to roughly 22 million tons of CO2 absorbed every day. Now, less CO2 in the atmosphere means decreased rates of climate change — a rather convenient setup for human development, right? Problem is, despite its size, the ocean can only process a certain level of atmospheric CO2 before underwater ecosystems begin suffering some impacts.
Increases in anthropogenic CO2 emissions over the last 200 years have led to dramatic changes in the ocean’s carbonate chemistry. When CO2 dissolves in seawater, the ocean’s pH drops. This makes the seawater more acidic and reduces the availability of carbonate ions, from which calcifying organisms (e.g. oysters, clams, plankton, corals) build their protective shells and skeletons. Since the Industrial Revolution, seawater has absorbed approximately 525 billion tons of human-produced CO2 and as a result, has become 30% more acidic. Ocean chemistry hasn’t experienced as rapid a change as this in over 50 million years.
Even though smaller, calcifying organisms are the most directly impacted, the repercussions of ocean acidification reverberate through every coastal and aquatic ecosystem. Sooner or later, we’ll all be on one bad acid trip.