Climate-Volcanism Feedback and the Toba Eruption of ∼74,000 Years Ago

• Published in: Quaternary Research
• Main Authors: Rampino, Michael R., Self, Stephen
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1993
• Subjects: Sea ice
• Online Access: http://dx.doi.org/10.1006/qres.1993.1081; http://api.elsevier.com/content/article/PII:S0033589483710811?httpAccept=text/xml; http://api.elsevier.com/content/article/PII:S0033589483710811?httpAccept=text/plain; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400034906

Abstract A general feedback between volcanism and climate at times of transition in the Quaternary climate record is suggested, exemplified by events accompanying the Toba eruption (∼74,000 yr ago), the largest known late Quaternary explosive volcanic eruption. The Toba paroxysm occurred during the δ 18 O stage 5a-4 transition, a period of rapid ice growth and falling global sea level, which may have been a factor in creating stresses that triggered the volcanic event. Toba is estimated to have produced between 10 15 and 10 16 g of fine ash and sulfur gases lofted in co-ignimbrite ash clouds to heights of at least 32 ± 5 km, which may have led to dense stratospheric dust and sulfuric acid aerosol clouds. These conditions could have created a brief, dramatic cooling or "volcanic winter," followed by estimated annual Northern Hemisphere surface-temperature decreases of ∼3° to 5°C caused by the longer-lived aerosols. Summer temperature decreases of ⩾10°C at high northern latitudes, adjacent to regions already covered by snow and ice, might have increased snow cover and sea-ice extent, accelerating the global cooling already in progress. Evidence for such climate-volcanic feedback, following Milankovitch periodicities, is found at several climatic transitions.