"In response to carbon dioxide-induced warming, the global water cycle undergoes a gigantic competition for moisture resulting in a global pattern of increased heavy rain, decreased moderate rain, and prolonged droughts in certain regions," lead study author William Lau of NASA's Goddard Space Flight Center in Greenbelt, Md. said Friday.
The predictions are based on an analysis of 14 climate models, and the study has been accepted for publication in the American Geophysical Union journal Geophysical Research Letters. A montage showing the model simulations is available here along with more details on the study.
Areas expected to see the most increase in rainfall are already familiar with rain. They are tropical zones around the equator, particularly in the Pacific Ocean and Asian monsoon regions. Areas likely to see less rain include the deserts and dry regions of the southwest United States.
One of the study's more significant predictions is that moderate rainfall around the globe could decrease and be replaced by either more rain or more drought. "Large changes in moderate rainfall, as well as prolonged no-rain events, can have the most impact on society because they occur in regions where most people live," Lau said. "Ironically, the regions of heavier rainfall, except for the Asian monsoon, may have the smallest societal impact because they usually occur over the ocean."