The water cycle -- the worldwide phenomenon of rainwater falling to the surface, evaporating back into the air and falling again as rain -- is changing, with the wetter parts of the world getting wetter and the drier parts drier, researchers report in Science magazine.
This is confirmed by the fact that saltier parts of the ocean are getting saltier and the fresher parts are getting fresher, they said.
"Salinity shifts in the ocean confirm climate and the global water cycle have changed," said Paul Durack of the University of Tasmania, who is now a post-doctoral fellow at Lawrence Livermore Laboratory in California.
The relationship between salinity in the sea and the water cycle is well documented, the researchers said.
Warmer air from climate change can absorb more water than cooler air, so as the climate warms, more water can evaporate into the air.
That affects the water cycle on both ends of the spectrum, the scientists said; in places where rainfall exceeds evaporation, the rain is increasing, in the places where evaporation rates are higher than rainfall, it gets drier.
The change in the water cycle is a significant concern, Durack said.
"Changes in the global water cycle and the corresponding redistribution of rainfall will affect food availability, stability, access and utilization," Durack said. "I come from Perth, in dry western Australia, and you can see the change."