Changes in global water cycle

© 2005 Eugene S. Takle

Will global warming bring more precipitation or less precipitation? The conclusion of Bosilovich et al. (2005) is, it depends. In the latter part of the 20th century, the Earth experienced a rise in temperature that was accompanied by a rise in precipitation. This increased the residence time of water vapor in the atmosphere and hence a reduction in the cycling time for moisture. By use of an ensemble of global models simulating the 20th century, Bosilovich et al. (2005) find an increasing trend in precipitation over ocean areas and a decreasing trend over land. The decreases over land are not uniform, however, with most decreases being over the tropics. Over North America, the precipitation trend of the models showed an increase, with a decrease over the Gulf of Mexico (both being counter to the global trends for land and ocean). This led to increased continental recycling of water over the US.

Reference

Bosilovich, M.G., S.D. Schubert, and G.K. Walker, 2005: Global changes of the water cycle intensity. J. Climate, 18, 1591-1608.