OCEAN ACIDIFICATION TO HIT LEVELS NOT SEEN IN 14 MILLION YEARS
Since the beginning of the industrial era, the ocean has absorbed around 525 billion tons of carbon dioxide (CO2), which equates to around 22 million tons a day – a 43 percent increase from the start of the Industrial Revolution. This amount is only a third of the CO2 released by burning coal, oil and gas. At this rate, ocean acidification is likely to hit unprecedented levels not seen in 14 million years, according to a study led by Cardiff University.
When the ocean absorbs CO2 from the atmosphere, the seawater becomes more acidic, with a lower pH. The rapid intake of CO2 is severely threatening marine life – shells of some animals are already dissolving due to high acid levels. Another study conducted by researchers at the University of Exeter found that rising acidity is causing fish to lose their sense of smell. This is affecting their ability to find food and respond to predators, in addition to the impact of CO2 on their central nervous system.
Comparing the chemistry of fossils of tiny sea creatures that once lived near the ocean surface to the new records of CO2 levels, scientists found that if we continue to emit carbon at the current rate, atmospheric CO2 would be reaching 930 parts per million in the year 2100, compared to around
400 parts per million today. These levels were seen 14 million years ago during the Middle Miocene Climatic Optimum period, when global temperatures were around three degrees Celsius warmer than today as a result of the Earth’s natural geological cycle.
Professor Carrie Lear, co-author of the study, explains, “The current pH is already probably lower than any time in the last two million years. Understanding exactly what this means for marine ecosystems requires long-term laboratory and field studies as well as additional observations from the fossil record.”
ABOVE A sea snail’s shell that has been damaged from high levels of seawater acidity