Model simulations spanning 140 years show warming from carbon dioxide will change the frequency that regions around the planet will receive rain, and while periods of no rain and heavy rain will increase, moderate rainfall will decrease, the space agency said Friday.
The study shows for the first time how rising carbon dioxide concentrations could affect the entire range of rainfall types on Earth, the researchers said.
"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 author William Lau of NASA's Goddard Space Flight Center in Greenbelt, Md., said.
Areas projected to see the most significant increase in heavy rainfall are in the tropical zones around the equator, particularly in the Pacific Ocean and Asian monsoon regions, while some regions outside the tropics may have no rainfall at all, the study suggests.
"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."