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Changes in the global water cycle critically impact environmental, agricultural, and energy systems relied upon by humanity (Jimenez Cisneros et al 2014 Climate Change 2014: Impacts, Adaptation, and Vulnerability (Cambridge: Cambridge University Press)). Understanding recent water cycle change is essential in constraining future projections. Warming-induced water cycle change is expected to amplify the pattern of sea surface salinity (Durack et a1 2012 Science 336 455-8). A puzzle has, however, emerged. The surface salinity pattern has amplified by 5%-8% since the 1950s (Durack et al 2012 Science 336 455-8, Skliris et al 2014 Clim. Dyn. 43 709-36) while the water cycle is thought to have amplified at close to half that rate (Durack et al 2()12 Science 336 455-8, Skliris et a1 2016 Sci. Rep. 6 752). This discrepancy is also replicated in climate projections of the 21st century (Durack et al 2012 Science 336 455-8). Using targeted numerical ocean model experiments we find that, while surface water fluxes due to water cycle change and ice mass loss amplify the surface salinity pattern, ocean warming exerts a substantial influence. Warming increases near-surface stratification, inhibiting the decay of existing salinity contrasts and further amplifying surface salinity patterns. Observed ocean warming can explain approximately half of observed surface salinity pattern changes from 1957-2016 with ice mass loss playing a minor role. Water cycle change of 3.6% +/- 2.1% per degree Celsius of surface air temperature change is sufficient to explain the remaining observed salinity pattern change.