Timing of Holocene volcanic eruptions and their radiative aerosol forcing

Volcanic eruptions play a dominant role in driving climate, in ways beyond the established short-term influence on surface air temperatures. In order to mitigate and adapt to the climate effects of future large volcanic eruptions we need to better quantify the risk of these eruptions including 1) the probability of their occurrence and 2) their expected climatic impact. The observational record of the timing of volcanic eruptions, their locations, magnitudes of sulphate aerosol injection is incomplete which limits our understanding of the sensitivity of the Earth system to volcanism and the vulnerability of social and economic systems to the climate impact of past and future eruptions.

The primary goal of this proposal is to extract data on the timing, magnitudes and source locations of all major volcanic eruptions occurring during the Holocene (i.e., the past 12,000 years) to answer the questions: What is the likelihood of a stratospheric sulphur injection as large as that from the colossal eruption of Tambora in 1815 to occur somewhere on the globe within the next 100 years? What is the role of effusive eruptions on past, present and future climate?

This will be achieved by employing novel, precisely dated, high-time resolution aerosol measurements from bipolar ice-core arrays. New tools will be used to constrain source parameters of the eruptions (location, plume injection height) that control their effects on climate. THERA will constrain recurrence rates for one of the largest global-scale natural hazards, while also assessing linkages between volcanic perturbations and key components of the climate systems (e.g., atmospheric circulation, droughts, ice-sheets and sea-level) through interdisciplinary case studies. As a final goal, THERA will generate global-scale, space-and-time resolved stratospheric aerosol properties for climate models to simulate the volcanic influence on Holocene climate evolution.