Variations in stratospheric aerosol -- arising primarily from sporadic volcanic eruptions -- are an important contributor to climate variability. Major volcanic eruptions have led to pronounced decreases in global surface temperature over seasonal-to-decadal timescales.

The transition from the unusual 1998-2002 period of a “fully decayed to quiescence” stratospheric aerosol layer, into a more typical period of modest volcanic activity temporarily offset a substantial proportion of the subsequent decadal forcing from increased greenhouse gases.

Advancing our understanding of the influence of volcanoes on climate relies upon better knowledge of the radiative forcings of past eruptions and the microphysical, chemical and dynamical processes which affect the evolution of stratospheric aerosol properties. This can only be achieved by combining information from satellite and in-situ observations of recent eruptions, stratospheric aerosol modelling activities, and reconstructions of past volcanic histories from proxies.

This session seeks presentations from research aimed at better understanding the stratospheric aerosol layer and its volcanic perturbations through the post-industrial period (1750-present) and also those further back in the historical record.

This year contributions addressing volcanic influences on atmospheric composition, such as changes in stratospheric water vapour, ozone and other trace gases are also particularly encouraged.

The session also aims to highlight research on volcanoes and climate contributing to current international SPARC-SSiRC, CMIP6-VolMIP, CMIP6-PMIP, and PAGES-VICS co-ordinated activities.