As Earth warms, melting glaciers and polar ice release more water. Thus, a wetter world for everyone, right?
That will depend, climate scientists say, on the complexities of rising temperatures and the hydrologic cycle, water's circular journey between liquid and vapor.
If warming continues at its present pace, stand by for more and higher water along the coasts as the oceans rise. But elsewhere in the country, precipitation will be key — and unpredictable.
Generally, climate researchers expect more precipitation in the USA by the middle of the 21st century. But with higher temperatures, more may fall as rain than as snow. Greater warmth would cause it to evaporate faster, too. Precipitation also may arrive heavier and harder, in more severe storms and intense hurricanes.
"Precipitation is going every which way," says Steve Running, a University of Montana forest ecologist and warming specialist. "We know it's already getting warmer and will continue to, but we can't actually answer whether it's going to get wetter or drier."
Here in the semi-arid West, bet on dry.