Changing patterns of salinity in the global ocean during the past 50 years show a clear fingerprint of climate change on the shift in worldwide rainfall and evaporation, they said.
Scientists with the Lawrence Livermore National Laboratory in California along with colleagues at Australia's Commonwealth Scientific and Industrial Research Organization say the Earth's water cycle has strengthened by 4 percent 1950-2000.
The cycle represents the ratio of rainfall rates with rates of evaporation.
"These changes suggest that arid regions have become drier and high rainfall regions have become wetter in response to observed global warming," LLNL researcher Paul Durack said.
Changes in ocean salinity can be directly linked to climate change, researchers said.
While land-based data of rainfall and evaporation are sparse, they said, global oceans provide a much clearer picture.
"The ocean matters to climate -- it stores 97 percent of the world's water; receives 80 percent of the all surface rainfall and it has absorbed 90 percent of the Earth's energy increase associated with past atmospheric warming," co-author Richard Matear of CSIRO said in a release Monday.
With oceans accounting for 71 percent of the global surface area, the change in the patterns of exchange between evaporation and rainfall is clearly represented in changes in ocean surface salinity patterns, he said.