This study was motivated by observations of significant salinification of the upper Eurasian Basin that began around 1989. Observational data and modeling results provide evidence that increased arctic atmospheric cyclonicity in the 1990s resulted in a dramatic increase of the salinity in the Eurasian Basin. Two mechanisms account for the Laptev Sea salinization: eastward diversion of Russian rivers and increased brine formation due to enhanced ice production in numerous leads in the Laptev Sea ice cover. Both these mechanisms are linked to changes in wind patterns and were essential to the formation of salinity anomalies. The resulting Laptev Sea salinity anomaly was advected to the central Eurasian Basin. The strong salinization over the Eurasian Basin altered the formation of cold halocline waters, weakened vertical stratification, and released heat upward from below the cold halocline layer. Our analysis suggests that local processes in the Laptev Sea may have a basin-wide impact on the thermohaline structure of the Arctic Ocean. ¿ 2001 American Geophysical Union