The volcanic eruption of 1258 A. D. and the subsequent ENSO event

The massive volcanic eruption of 1258 A. D. had far-reaching climate and demographic impacts [Stothers, 2000; Oppenheimer, 2003]. Although the identity of the volcano responsible for the eruption remains a mystery, a tropical location is likely, given the worldwide presence of the ashes and simultaneous presence of its signal in ice cores from both poles. Using estimates of its radiative effect [Crowley, 2000] and a climate model of intermediate com-plexity [Zebiak and Cane, 1987], we show that the eruption is likely to have triggered a moderate-to-strong El Ni?o event in the midst of prevailing La Ni?a-like conditions. Disparate paleoclimate data document important hydroclimatic consequences for neighboring areas. We propose, in particular, that the event briefly interrupted a solar-induced megadrought in the Southwestern US.