Coral reef ecosystems are often labeled as “robust,” able to survive disturbance, or “resilient,” able to recover after a disturbance, in terms of their ability to adapt or acclimatize to global change. Those labels are now fading in light of findings of a symposium and workshop to readdress the question, How will coral reefs fare under the increasing stresses associated with global change? In fact, coral reef ecosystems appear to be directly threatened by globally increasing atmospheric CO2. By altering sea surface chemistry, specifically by lowering the carbonate ion activity, rising CO2 levels will most certainly reduce calcification rates of the major reef-building organisms individually, and coral reef communities overall. A reduction in coral reef carbonate production could have profound ecological effects on these marine ecosystems and organisms associated with them.