Coral still has a chance if the maximum CO2 concentration in the atmosphere can be limited. It's another reason for energy efficiency and reduction of CO2 emissions.
They say that we can keep global temperatures from rising 2C by cutting CO2 emissions by 25% to 80% (depending on which shaman you listen to) over 1990 levels by 2050. Do you really believe that this is even remotely possible given most of the world is over 1990 levels and the developing world is 2-3 times their 1990 levels.