Ocean Salinities Reveal Strong Global Water Cycle Intensification During 1950 to 2000, by Paul J. Durack, Susan E. Wijffels & Richard J. Matear, Science 336(6080) (April 27, 2012); doi: 10.1126/science.1212222

Science (27 April 2012), Vol. 336, No. 6080, pp. 455-458; doi: 10.1126/science.1212222                         

Ocean Salinities Reveal Strong Global Water Cycle Intensification During 1950 to 2000

Paul J. Durack¹,²,³,⁴,*, Susan E. Wijffels¹,³, and Richard J. Matear¹,³

Abstract

Fundamental thermodynamics and climate models suggest that dry regions will become drier and wet regions will become wetter in response to warming. Efforts to detect this long-term response in sparse surface observations of rainfall and evaporation remain ambiguous. We show that ocean salinity patterns express an identifiable fingerprint of an intensifying water cycle. Our 50-year observed global surface salinity changes, 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. 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.

¹Centre for Australian Weather and Climate Research, Commonwealth Scientific and Industrial Research Organisation (CSIRO) Marine and Atmospheric Research, General Post Office (GPO) Box 1538, Hobart, Tasmania 7001, Australia

²Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tasmania 7001, Australia

³Wealth from Oceans National Research Flagship, CSIRO, GPO Box 1538, Hobart, Tasmania 7001, Australia

⁴Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory, Mail Code L-103, 7000 East Avenue, Livermore, CA 94550, U.S.A.

*Correspondence e-mail: pauldurack@llnl.gov