A CRITICAL OVERVIEW OF THE ENVIRONMENTAL, CLIMATIC AND HUMAN IMPACTS OF THE ~74 KYR BP TOBA “SUPER-ERUPTION”

The magnitude 8.8 eruption of the Younger Toba Tuff (YTT) has been on the ‘radar screen’ of volcanologists for decades, and more recently that of paleoanthropologists, archaeologists, zoologists and climate scientists. The debates concerning the environmental and human consequences of the eruption have also featured on our TV screens in docudramas and documentaries. Given the colossal size of the eruption, and its comparatively recent occurrence (perhaps a few millennia after ‘anatomically modern humans’ made their decisive exodus from Africa) it is unsurprising that some of the most far-reaching claims for the effects of volcanism on global climate and humanity have been made for the YTT. The anthropologist Stanley Ambrose has led the camp arguing for dramatic consequences for human populations. In his words, “When the modern African human diaspora passed through the prism of Toba’s volcanic winter, a rainbow of differences appeared.” But how does the evidence behind the arresting claims for hold up to scrutiny? I shall review the arguments and the volcanological, paleoenvironmental and modeling evidence behind them. I shall also present preliminary interpretations emerging from ongoing studies of the YTT fallout and associated sedimentological contexts in India.