Ocean Acidification — This Is Far Worse Than Sea Levels Rising
Plankton form the bedrock of the marine food web but their existence and that of the entire marine food web is threatened by the oceans becoming more acidic
“Everyone bangs on about rising sea levels but the real challenge of a warming planet is ocean acidification. An acid ocean spells the end of life on earth.” — Tim Winton
The first time I learnt about ocean acidification was from my high school chemistry teacher. In a few short minutes, he explained to me that not only was the combustion of fossil fuels contributing to the enhanced greenhouse effect, the atmospheric carbon dioxide was reacting with the water of the oceans, turning into carbonic acid.
This would render the ocean uninhabitable for marine organisms, threatening the fundamental underlying chemical equilibrium within the oceans. If this continues, the food web will collapse, our coral reefs will die .
We’re not talking about the extinction of one species, we’re talking about the end of the entire hydrosphere ecosystem.
What is ocean acidification?
Since the Industrial Revolution, the amount of atmospheric carbon dioxide has been steadily rising due to the burning of fossil fuels.
Not only is this increase in carbon dioxide bad as it contributes to the enhanced greenhouse effect, it is directly contributing to making our oceans more acidic.
The oceans absorb approximately 30% of atmospheric carbon dioxide. Carbon dioxide is able to dissolve in water where is can then react with water to form carbonic acid.
As we burn more fossil fuel, we release more CO2 into the atmosphere. The CO2 is absorbed by our oceans, resulting in carbonic acid forming. The acid releases hydrogen ions into the oceans, which compete with calcium for carbonate. If the hydrogen wins, then the abundance of calcium carbonate decreases.
Why is ocean acidification dangerous?
Ocean acidification threatens the entire marine ecosystem.
All biological organisms require a narrow range of environmental parameters to be able to survive and thrive. If it’s too hot or too cold, too acidic or too alkaline, they die.
In this case, ocean acidification reduces the availability of important calcium carbonate minerals, which are essential for many marine organisms to build their skeletons and shells.
The oceans are predicted to be so corrosive by 2100 that the ocean will literally corrode the shells of sea life.
Furthermore, plankton are the most abundant organism in the ocean and form the foundation of the marine food web — all marine life depend on them for food. Phytoplankton (plankton that photosynthesise) are responsible for producing the majority of the oxygen on Earth, 2x more than what trees produce. However, ocean acidification has been especially damaging to them, as it disrupts the “biological-carbon pump that drives photosynthesis”, depressing their metabolic rate and impeding their normal functions.
If the plankton die, then the rest of the food web dies with them.
How will this affect the rest of world?
More than three billion people rely on the oceans for their income or source of food, with the vast majority of them living in the developing world. Ocean acidification will disproportionately affect those who had the least to do with it.
The World Wildlife Fund conservatively estimates the value of the ocean to be $24 Trillion, with $2.5 Trillion in goods and services being produced each year from it, yet this value is rapidly diminishing as the oceans become increasingly damaged.
Industries such as fishing and tourism will be threatened. In addition, our coastlines risk deterioration due to ocean acidification contributing to coral bleaching. Without coral reefs to act as protection against storm surges and cyclones, we may end up losing billions of dollars a year due to property damage and erosion.
How bad is it going to get?
Since the start of the Industrial Revolution, the pH of the ocean has fallen by 0.1. As the pH scale is a logarithmic scale like the Richter scale, a decrease in 0.1 pH means a 25% increase in the acidity of the oceans.
To put this into perspective, a drop of 0.1 pH in our blood would induce acidosis, leading to seizures, heart arrhythmias and or even a coma.
Furthermore, prediction models by climate scientist cast a bleak outlook on the future. The latest prediction models estimate that future carbon dioxide levels in the oceans will reach 800ppm in 2100, corresponding to a 150% increase in ocean acidity. The last time the oceans were this acidic was 20 million years ago except this time, the levels are changing too fast for marine life to be able to properly adapt.
What is being done to stop this?
The best way to help fight against this would be to reduce carbon dioxide emissions. The UN Sustainable Developmental Goals and the Paris Accords are steps in the right direction but they leave much to be desired.
“Most countries aren’t hitting 2030 climate goals, and everyone will pay the price” — National Geographic
A potential solution proposed by marine biologists is geo-engineering, whereby growing seagrass meadows may help decrease the local acidity and allow marine life to recover.
Working to reduce ocean acidification is especially important as there is no quick and easy fix to rising acidity. If the levels of atmospheric carbon dioxide suddenly returned to normal, the ocean’s pH would remain acidic. It would only be through the weathering and dissolving of rocks that the acid would be neutralised and equilibrium restored. As this process is very slow, our oceans would be corrosive for a long period of time before healing.
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