1Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany
2Institute of Environmental Physics, University of Bremen, Bremen, Germany
3NOAA ESRL Chemical Sciences Division, Boulder, CO, USA
4California Institute of Technology, Pasadena, CA, USA
5Atmospheric and Environmental Research, Inc., Lexington, MA, USA
6Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel, Germany
*now at: University of Oslo, Oslo, Norway
Abstract. Hundreds of biogenic and anthropogenic chemical species are emitted into the atmosphere. Most break down efficiently by reaction with OH and do not reach the stratosphere. Here we show the existence of pronounced minima in the tropospheric columns of ozone and OH over the West Pacific, the main source region for stratospheric air. We show that this amplifies the impact of surface emissions on the stratospheric composition. Specifically, emissions of biogenic halogenated species from natural sources and from kelp and seaweed farming can have a larger effect on stratospheric ozone depletion. Increasing anthropogenic emissions of SO2 in South East Asia or from minor volcanic eruptions can play a larger role for the stratospheric aerosol budget, a key element for explaining the recently observed decrease in global warming rates (Solomon et al., 2011).