Most attention regarding climate change is focused on the effects of greenhouse gases, on changes in the distribution of radiative energy, on changes in weather patterns and on the multitude of consequences accompanying those changes. Precipitation - a crucial factor for life on Earth - is one of the parameters of great concern.

Going beyond the detail with which the impacts of anthropogenic aerosol and changes in natural aerosol on precipitation are treated in the IPCC reports, the WMO/IUGG International Aerosol Precipitation Science Assessment Group developed a review that was completed earlier this year.

The IAPSAG report details what is known of the relationship between aerosols and precipitation, highlights uncertainties of this complex subject and makes recommendations for future work. A summary of the report will be given, with some personal views added.