The world's oceans are in danger of hitting the highest acid levels in 14 million years if the rate of carbon dioxide emissions does not slow down.
Researchers at the Cardiff University in Wales have found that, if power-producing plants continue to pump the same amount of carbon dioxide into the atmosphere, the world's oceans will reach acidification levels that have not happened since the Middle Miocene Period.
The researchers believe that the current acid levels of the world's oceans are already at their peak in the last 2 million years, as can be seen in the rapid degradation of marine life.
Highest Acid Levels Since The Middle Miocene
In a new study published in Earth and Planetary Science Letters, the researchers say the ocean's acid levels will rise to unprecedented heights by the end of the century if carbon dioxide emissions from human activity are not reduced.
"Our new geological record of ocean acidification shows us that on our current 'business as usual' emission trajectory, oceanic conditions will be unlike marine ecosystems have experienced for the last 14 million years," says lead author Sindia Sosdian of the School of Earth and Ocean Sciences at Cardiff.
By analyzing the fossils of marine creatures, Sosdian and her team were able to determine the levels of acidity and atmospheric carbon dioxide over the last 22 million years. They specifically examined the shells of these creatures to find out the acidity levels in the seawater.
If carbon dioxide emissions continue at the current rate, atmospheric carbon dioxide will rise to 930 parts per million in 2100. Currently, atmospheric levels of carbon dioxide are at 400 parts per million.
Similarly, the pH level of the world's oceans will drop to 7.8 by the end of the century, compared to the pH level of 8.1 today. This is an enormous leap down the pH scale since a 0.1 decrease in pH means a 25 percent rise in acidity.
Implications For Marine Life
Acid levels in the world's oceans rise when seawater absorbs more carbon dioxide from the atmosphere. When the ocean interacts with carbon dioxide, a chemical reaction occurs that produces carbonic acid.
These results in more acidic water that corrodes coral reefs and threatens shellfish and other marine species. An earlier study done in the Great Barrier Reef shows that, if carbon dioxide emissions continue at the rate they are going, ocean acidification will severely impair the growth of coral reef before the next century begins.
Reefs and shellfish, in particular, are vulnerable to rising acid levels because their skeletons and shells are made from calcium. As seawater becomes more acidic, calcification becomes more difficult.
Since the onset of industrial era in the 18th century, the world's oceans have absorbed as many as 525 billion tons of carbon dioxide. This is equivalent to around 22 million tons every day.
It has long been established that emissions from burning coal, oil, and gas are the biggest contributors to rising atmospheric levels of carbon dioxide. As much as a third of these emissions are absorbed by the world's oceans.