8. Environmental and climatic effects from atmospheric SO2 mass-loading by Icelandic flood lava eruptions

Abstract

Publisher Summary Volcanic eruptions are dynamic and multifaceted events that affect the environment in various ways, both locally and remotely. In areas remote to the volcano, the effects of the eruptions are confined to the atmosphere and widespread volcanic aerosol plumes have resulted in significant perturbations on a hemispheric to global scale. Flood lava eruptions are capable of releasing huge amounts of sulphur into the atmosphere, because of the high sulphur yield of basaltic magmas coupled with extremely efficient vent degassing in the recurring explosive phases. Prolonged flood lava eruptions can maintain elevated atmospheric concentrations of H 2 SO 4 aerosols for periods of months to years. Studies have emphasized the significance of flood lava eruptions for short-term environmental and climate changes while others have pointed out the apparent association of flood basalt volcanism with major climatic excursions in the past. This chapter provides an overview of the atmospheric sulphur mass loadings and effects of the three largest Holocene flood lava eruptions in Iceland. The chapter focuses on the potential impact of the Eldgja and Pjorsa eruptions.