The sudden onset of ozone depletion in the Antarctic vortex set a precedent for both the time scale and the severity of global change. The AIRBORNE ANTARCTIC OZONE EXPERIMENT (AAOE) staged from Punta Arenas, Chile, in 1987, established that CFCs and Halons are the source of chlorine and bromine radicals that, in turn, control the rate of ozone destruction, that the vortex is depleted in nitrogen oxides, reactive nitrogen, and water vapor and that diabatic cooling during the antarctic winter leads to subsidence within the vortex core importing air from higher altitudes and lower latitudes.