By: David McDonald
Everyone learns about pH levels in science class, but nowhere does the high school curriculum (at least when I was in high school) teach you about the adverse effects of the acidification of our oceans.
So how does ocean acidification work?
The burning of fossil fuels releases CO2 into our atmosphere, which causes climate change. This is widely known, but what most don’t know is that our oceans absorb roughly 25 to 30 percent of CO2 emissions. This process is slowly acidifying our seas which in turn, changes the delicate biology of the ocean.
At the beginning of the Industrial revolution (1780s) our oceans had a pH level of 8.2. Today, it is about 8.1. Although the change may seem small, similar shifts have taken 5,000 to 10,000 years. We have done it in under 200 years. According to scientists, emissions could reduce surface pH by another 0.4 unit in this century alone. This number could increase by as much as 0.7 beyond 2100. These numbers may not seem substantial at first glance, but similar natural changes in history have caused several mass extinctions throughout the earth’s waters, and it could happen again sooner than we think.
Increasing carbon dioxide levels in the ocean affect all marine species alike. When CO2 dissolves in seawater, it slowly changes the chemistry of the ocean, making it harder to organisms to make skeletons, breathe, and migrate. It is an open question as to how marine life will cope with the changing ocean environment, but one thing is for sure – some species will suffer.
Our understanding of this process right now is not great, but history has shown that a mass ocean extinction can indeed happen. 96 percent of ocean life went extinct during the Permian mass extinction 248 million years ago. Coincidentally, ocean acidification was a large driver in the extinction of ocean life. Now the method of acidification was obviously different, as a series of volcanic eruptions caused massive CO2 emission to pour into the ocean and subsequently, kill everything. What we are doing is a far stretch from a mass extinction, but it is still enough to change the biology of our oceans, and the way we live.
Although man-made climate change will be much milder than this event, immediate action to stabilize CO2 levels is crucial to minimize our disruption of ocean chemistry and ecosystems. We can no longer deny our role in global climate change. We must prioritize clean energy efforts and find every way possible to decrease our carbon emissions into the atmosphere if we are to avoid another mass extinction of our oceans.\