Acid Ocean Facts

1. Up to one half of the carbon dioxide (CO2) released by burning fossil fuels over the past 200 years has been absorbed by the world’s oceans

2. Absorbed CO2 in seawater (H2O) forms carbonic acid (H2CO3), lowering the water’s pH level and making it more acidic

3. This raises the hydrogen ion concentration in the water, and limits organisms’ access to carbonate ions, which are needed to form hard parts

Up to 50% of the CO2 released by burning fossil fuels over the past 200 years has been absorbed by the world’s oceans

This has lowered the pH value of seawater – the measure of acidity and alkalinity – by 0.1

The vast majority of liquids lie between pH 0 (very acidic) and pH 14 (very alkaline); 7 is neutral

Seawater is mildly alkaline with a "natural" pH of about 8.2

The IPCC forecasts that ocean pH will fall by "between 0.14 and 0.35 units over the 21st Century, adding to the present fall of 0.1 units since pre-industrial times"

In September, the UN-backed study into The Economics of Ecosystems and Biodiversity (Teeb) concluded that the widely-endorsed target of trying to stabilise atmospheric concentrations of CO2 or their equivalent to around 450 parts per million (ppm) would prove lethal to much of the world’s coral.

"Unlike global warming, which can manifest itself in nuanced, complex ways, the science of ocean acidification is unambiguous," said Andrew Dickson, a Scripps professor of marine chemistry.

"The chemical reactions that take place as increasing amounts of carbon dioxide are introduced to seawater have been established for nearly a century."

(BBC – full article)