Ocean water-cycle intensity increasing, say researchers
A new study of the ocean's changing salinity confirms that the water cycle is intensifying quickly under global warming - twice as fast as climate models have been predicting.The report, Ocean Salinities Reveal Strong Global Water Cycle Intensification During 1950 to 2000 by a US/Australia team of Paul J Durack, Susan E Wijffels and Richard J Matear, looked at 50 years of ocean salinity changes.
Fundamental thermodynamics and climate models suggest, say the authors, that, in response to global warming, dry regions will become drier and wet regions will become wetter. Efforts to detect this long-term response in sparse surface observations of rainfall and evaporation remain ambiguous.
The observed global surface salinity changes logged by the researchers, combined with changes from global climate models, present robust evidence of an intensified global water cycle at a rate of 8 ± 5% per degree of surface warming, they say. This rate is double the response projected by current-generation climate models and suggests that a substantial (16-24%) intensification of the global water cycle will occur in a future 2-3°C warmer world.