Introduction In the 16 September 2005 issue of Science, large and unexpected changes in the climate of the North Atlantic ocean are reported by a team of climate scientists from the Faroe Islands, Norway and Iceland. It is shown that the oceanic waters off Northern Europe are exhibiting record-high temperatures and salinities, and that these extremes relate to changes in the circulation in the North Atlantic Ocean since the mid-90s. Modelled salinity in the North Atlantic. Red colours show saline (and warm) water masses, blue colours show fresh (and colder) water masses. The Faroe Islands are located half way between northern Scotland and Iceland. See Geography and water masses for information about the figure. Observations of temperature and salinity in the oceans around Norway, the Faroes, Scotland and Iceland show record high values since the measurements started in 1948. In the study, these observations are combined with satellite observations and an advanced numerical ocean model to disclose and understand the increases in these parameters. It is shown that the record highs of temperature and salinity are due to decade-long reduction in the extension of the cold and fresh waters south of Iceland and Greenland. This has allowed for transport of very warm and saline waters into the Nordic Seas west of the Faroes and further along the Norwegian coast, and south of Iceland. These findings are remarkable since they indicate a reversal of an observed gradual freshening of the North Atlantic and the Nordic Seas since 1960, as a consequence of enhanced precipitation and melting of snow and ice, partially due to global warming. It is noted that this decrease in salinity alone could weaken the Gulf Stream system. The new observations - record-high ocean temperatures and salinity - are ascribed to changes in the circulation of the North Atlantic. They have important implications for the climate in northern Europe. On the one hand, the high salinity of the water masses will secure that the strength of the Gulf Stream system is maintained in the upcoming decades. On the other hand, the high temperatures will enhance the impacts of global warming on the climate of the Northern Hemisphere. It is unclear whether these changes are due to human influence on the climate system or if they are simply a consequence of natural variability of the North Atlantic climate system. In order to answer this, it is necessary to combine measurements of parameters of the ocean climate with advanced numerical modelling. References: Hátún, H., A. B. Sandř, H. Drange, B. Hansen, and H. Valdimarsson (2005), Influence of the Atlantic Subpolar Gyre on the Thermohaline Circulation, Science, 309, 1841-1844 [article]