State of The Climate in 2010: [Global Oceans] Oceans salinity: a water cycle diagnostic?

Present-day civilizations thrive in a wide range of temperatures at different latitudes across the Earth, but cannot cope without available freshwater. Changes to global water distribution are anticipated in the 21st century as anthropogenic climate change signatures become more apparent from natural variability of the climate system; future projections of surface moisture fluxes suggest that regions dominated by evaporation (over rainfall over the course of a year), will become drier, while regions dominated by rainfall (over evaporation) will become wetter (Allen and Ingram 2002; Held and Soden 2006; Meehl et al. 2007; Wentz et al. 2007; Seager et al. 2010). In water-stressed areas the human population and surrounding ecosystems are particularly vulnerable to decreasing or more variable rainfall due to climate change. Therefore, understanding probable future changes to the global water cycle are vital, as the projections of future climate show considerable changes to the water cycle are likely to significantly impact much of the world’s population.