The chemical composition of the middle atmosphere is not only relevant for understanding radiative forcing or protection of the biosphere from harmful UV radiation, but it also has an influence on tropospheric circulation and dynamics that act as a feedback on climate. Increasing greenhouse gases are expected to modify the large-scale circulation of the stratosphere, termed Brewer-Dobson circulation (BDC), and the chemical compositions of radiatively active gases, notably ozone and water vapour, in the upper troposphere and lower stratosphere (UTLS) region. Such changes in the BDC and UTLS composition are expected to change levels of surface UV radiation, modify the radiative forcing of climate, and feedback on the dynamics both within the stratosphere and at the surface. This session is particularly interested in evidence of the direct influence of climate change upon stratospheric dynamics and chemistry, as well as indirect feedbacks from these changes back upon surface climate. We welcome abstracts focused on stratospheric composition changes on time-scales encompassing inter-annual to centennial timescales,on local to global spatial scales, future projections from chemistry climate models, and discussing changes induced by both natural and anthropogenic factors, observations, as well as theoretical studies.