Anthropogenic versus natural sources of atmospheric sulphate from an Alpine ice core

Opposite to greenhouse gases, sulphate aerosol particles are expected to cause climate cooling, but uncertainties exist about source variability and strength. We analysed an ice core from a European glacier to quantify source strengths of aerosol-borne sulphate over a 200-year period. Sulphate from emissions of SO2 increased by more than an order of magnitude during this century. This anthropogenic source is responsible for about 80% of total sulphate in the industrial period, and reflects emissions of west European countries. In the pre-industrial period mineral dust was the dominant contributor, followed by sulphate from SO2 emissions with volcanoes or biomass burning as possible sources.