After analyzing global measurements of solar radiation and rainfall taken between 1986 and 2000, scientists at the Swiss Federal Institute of Technology in Zurich, have determined that global warming and cleaner skies are making it rain more.
According to a report in New Scientist, on an average, surface solar radiation has increased by 0.21 watts per square meter per year over land, and rainfall has increased by 3.5 millimeters per year.
"In recent decades, air pollution has dropped, so more sunlight is penetrating the atmosphere," said Martin Wild of the Swiss Federal Institute of Technology.
"This intensification of the water cycle means more heavy precipitation events, more flooding, and more landslides, erosion and overloading of water management systems," said Wild.
The analysis only covers land areas, so it isn't clear whether the extra rain is coming from increased evaporation over land or oceans.
According to Wild, the effects have not been distributed evenly.
Local factors, such as winds that carry rain elsewhere, mean some places have become drier, such as the south-west US and southern Asia.