[Illustrations, footnotes and references available in PDF version]
In a paper recently published in Geophysical Research Letters, Silverman et al. (2009) created a model of coral calcification based on field observations of gross community calcification as a function of aragonite saturation state (Ωarag), sea surface temperature (SST) and live coral cover, after which they calculated calcification rates for more than 9,000 reef locations using model values of Ωarag and SST at different atmospheric CO2 concentrations, which exercise led them to conclude that "by the time atmospheric partial pressure of CO2 will reach 560 ppm, all coral reefs will cease to grow and start to dissolve."
What’s wrong with this picture?
For starters – and as actually acknowledged by the researchers themselves – "coral reefs were exposed throughout their geological history to higher temperatures and CO2 levels than at present and yet have persisted," which is a pretty amazing admission for them to make, in light of the fact that they have boldly declared that when the atmosphere’s CO2 concentration reaches 560 ppm in the not too distant future, "all coral reefs will cease to grow and start to dissolve."