The water cycle is a term for how water evaporates from the ocean, forms clouds that deliver rain to the land, and how that rain returns to the sea flowing in streams or through the ground.
And now a new study predicts that, because of global warming, the water cycle is going the get a big boost.
That means that water will evaporate faster, the air will contain more humidity, and more rain will fall in some places. Since water vapor drives weather, a stronger water cycle will produce more extreme weather--such as hurricanes and tornadoes.
But areas that are already dry, such as the southwestern US, are likely to become dryer. Existing patterns of rainfall are going to be amplified.
A study published April 27 in Science (p. 405) found that the water cycle is going to increase much more than climate models have predicted. The study analysed actual changes in evaporation and rainfall over the oceans from 1950 to 2000.
While the ocean surface warmed by 0.5 C during that time, the water cycle sped up by about 4%.
"If the world warms 2 to 3 degrees C by the end of the century, as currently projected,... the water cycle will accelerate 16% to 24%...," according to Science.
For Madison, this suggests more intense flooding. Measures for handling stormwater will have to be beefed up, hopefully with the addition of more green infrastructure. Erosion control procedures will have to improve, to cope with more intense rainfall.