A recent study by Martin Wild and his colleagues, from the Swiss Federal Institute of Technology in Zurich have shown that solar radiation and rainfall have increased with the decrease in air pollution.
Martin explains that as air pollution drops over recent decades, due to new and more stringent emission standards, the solar radiation increases because more sunlight is able to penetrate the atmosphere. This increase in solar radiation has caused an increase in evaporation, thus intensifying the natural water cycle and ultimately causing more rain. This excess rain could explain some of the extraordinary recent precipitation events, such as flooding, landslides and erosion.
Wild’s study has only focused on land masses, so it is not yet clear as to whether these precipitation increases are from evaporation over land masses or from the oceans. The effects of this phenomena are localized and some factors, such as increases in winds could cause less rain in particular areas, which would explain increase droughts in those areas.