SOURCE: Cardiff University

DATE: July 23, 2018

SNIP: The world’s oceans are likely to become more acidic than at any time in the past 14 million years, scientists have found.

New research led by Cardiff University has shown that under a ‘business-as-usual’ scenario of carbon dioxide (CO2) emissions, ocean acidification is likely to hit unprecedented levels.

Ocean acidification occurs when CO2 from the atmosphere is absorbed by seawater, resulting in more acidic water with a lower pH.

Around a third of the CO2 released by burning coal, oil and gas gets dissolved into the oceans. Since the beginning of the industrial era, the ocean has absorbed around 525 billion tons of CO2, equivalent to around 22 million tons per day.

The rapid influx of CO2 in to the oceans is severely threatening marine life, with the shells of some animals already dissolving in the more acidic seawater.

Under a ‘business-as-usual’ future scenario where we continue to emit CO2 at the same rate as we do today, atmospheric CO2 would be near 930 parts per million in the year 2100, compared to around 400 parts per million today.

Similarly, the pH of the oceans would be less than 7.8 in 2100 compared to a pH of around 8.1 today. This is very significant as the pH scale is logarithmic, meaning a drop of just 0.1 pH units represents a 25% increase in acidity.

These levels of atmospheric CO2 and ocean acidity have not been since the Middle Miocene Climatic Optimum period around 14 million years ago, when global temperatures were around 3°C warmer than today as a result of the Earth’s natural geological cycle.