The top left figure shows changes in CO32- over time for the high emissions scenario (RCP8.5) and the low emissions scenario (RCP2.6) as well as the concentrations of [CO32-] where Ω = 1 (the saturation lines for aragonite and calcite, the two different mineral structures for CaCO3 – the oysters are aragonite). It is a complicated plot, but the key point is that [CO32-] is decreasing in all regions of the ocean, with much more pronounced decreases in the high emissions scenario. Remind students of the direct relationship between [CO32-] and Ω.
The two bottom plots on the left show Ω variations with depth in the Atlantic and Pacific oceans for 2100 following the high emissions scenario. The three plots on the right show Ω throughout the 21st century when following the high emissions scenario. Note the spatial variability in Ω throughout the ocean, with lower Ω in deeper waters and at higher latitudes.
IPCC AR5 pH and Omega
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