A study published in Nature Reports Climate Change on 11 June 2009 reports on the consequences of the emission targets being set by countries, including the US and Australia, in the lead-up to the international climate negotiations in Copenhagen in December.
Joeri Rogelj and colleagues conclude, “National targets give virtually no chance of constraining warming to 2 °C and no chance of protecting coral reefs.”
Citing recent publications of Jacob Silverman and colleagues, they note in relation to ocean acidification and coral reefs:
While we have focused on global mean temperature increase here, it is increasingly clear that independent of its effect on temperature, growing CO2 concentrations in the atmosphere will also threaten the world’s oceans owing to acidification. The latest research indicates substantial risk to calcifying organisms at atmospheric CO2 concentrations of 450 ppm, with all coral reefs halting their growth and beginning to dissolve at concentrations of 550 ppm. The best Halfway to Copenhagen emissions pathway would result in CO2 concentrations above this level shortly after 2050.
Unless there is a major improvement in national commitments to reducing greenhouse gases, we see virtually no chance of staying below 2 or 1.5 °C. Coral reefs, in addition, seem to have certainly no chance if the work of Jacob Silverman and colleagues is correct.