A model hindcast for 1948--2002 shows several warming events in the Atlantic layer of the Arctic Ocean. The most recent warming event in the 1990s spread from Fram Strait to the Lomonosov Ridge and into the Canadian Basin. Only a warming event in the 1960s can also be followed into the eastern Eurasian Basin. These two warming events are reinforced by anomalously warm flow from the Barents Sea while warming events in the 1970s and 1980s encounter average or below normal temperatures in the Barents Sea branch of the Atlantic Water. The warm Barents Sea outflow in the 1960s is caused by extensive ice cover and a melt water induced halocline in the Barents Sea that reduced heat loss from the Atlantic water. In the 1990s, however, the warm inflow from the Nordic Seas was responsible for warmer than normal flow from the Barents Sea into the Arctic Ocean.