Ocean acidification: state of scientific knowledge and infographic on aragonite saturation

Ocean Acidification Summary for Policymakers 2013
The unprecedented rate of ocean acidification is one of the most alarming phenomena generated by climate change and the only way to mitigate the dangers it represents consists in reducing CO2 emissions significantly. This is the conclusion of the summary of the Third Symposium on the Ocean in a High CO2 World (Monterey, USA, September 2012) which were presented today at the Conference on Climate Change taking place in Warsaw (Poland) from 11 to 22 November.

This summary for policymakers reports on the state of scientific knowledge on ocean acidification, based on the latest research presented at The Third Symposium on the Ocean in a High-CO2 World. Experts present the projected changes from ocean acidification for ecosystems and the people who rely on them, according to levels of confidence for these outcomes.

Infographic on aragonite saturation

Saturation state, Omega (Ω), describes the level of saturation of calcium carbonate in seawater. Shown here is the mineral form of calcium carbonate called aragonite.

If Ω is less than 1 (Ω<1), conditions are corrosive (undersaturated) for aragonite-based shells and skeletons.

When Ω>1, waters are supersaturated with respect to calcium carbonate and conditions are favourable for shell formation. Coral growth benefits from Ω ≥3.

By 2100, computer model projections show that Ω will be less than 3 in surface waters around tropical reefs if CO2 emissions continue on the current trajectory.