Air pollution is likely to have contributed to the catastrophic Sahel drought in Africa, according to Australian research. The research was carried out by Leon Rotstayn from Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) and his colleague Ulrike Lohmann from Canada's Dalhousie University. They ran a simulation of global weather including the interaction between sulphur dioxide emissions and cloud formation. Sulphur emissions from power stations and factories prevent cloud formation, cooling the Earth below. As this pollution mainly happened in the industrialized north, the Northern Hemisphere became relatively cooler than the south. This caused the rain belt to move south, away from the Sahel. Johann Feichter of the Max Planck Institute for Meteorology in Hamburg, Germany, says the sulphur emissions probably worsened the natural cycle of droughts that would have happened anyway.

Contact: Leon Rotstayn, CSIRO, leon.rotstayn@csiro.au; Paul Holper, CSIRO, paul.holper@csiro.au

Source: New Scientist, 12 Jun 2002
CSIRO, 13 Jun 2002