A water mass largely formed in the Labrador Sea and the Greenland Sea by the sinking of highly saline, dense water. It is part of the ‘conveyor belt’ model of the thermohaline circulation. It has been suggested that global warming may cause sufficient freshwater to be released from the melting of ice in the northern latitudes to slow or even to stop the formation of the NADW by reducing salinity to the level where it is insufficiently dense to sink. If this occurred it would stop the Gulf Stream flowing north, and thus cause the oceanic conveyor belt, which is transferring heat from the equator, to cease. This would have a dramatic cooling effect on the climate of north-west Europe (Krom in J. Holden (2012), p. 61).