Intensified double diffusive mixing may attenuate changes in ocean temperature and salinity patterns from global-warming induced increases in the Earth's hydrological cycle. Increasingly fresher Antarctic Intermediate Water and saltier subtropical waters would tend to increase destabilizing vertical salinity stratification compared to the stabilizing temperature stratification. Destabilization would increase salinity (and temperature) fluxes through double-diffusive salt fingering. These fluxes could in turn act to reduce widely recognized climate change fingerprints, potentially leading to underestimates of ocean changes in climate studies that do not account for double-diffusive mixing. Data from a subtropical trans-Indian Ocean survey occupied in 1987, 1995, 2002, and 2009 are used to investigate temperature-salinity changes and to estimate the variations of double diffusive mixing driven by these changes.