A shift in European climate in the 1990s to mild, wet summers in the north and hot, dry summers in the south is linked to the warming phase of an oscillation in North Atlantic Ocean temperatures, reports a study published online this week in Nature Geoscience. Until North Atlantic ocean temperatures swing back towards a cooler phase, this pattern is likely to persist.

Rowan Sutton and Buwen Dong analysed climate data derived from observations to investigate links between North Atlantic Ocean temperatures and European climate. They find that in the 1990s, European climate shifted considerably in the summer and, less clearly, in the spring and autumn. This shift coincided with substantial warming of the North Atlantic ocean, associated with a documented pattern of multi-decadal oscillations in Atlantic Ocean temperature. The authors suggest that the climate shifted in response to ocean warming. Based on an earlier transition, a return to the cool phase of this oscillation could be sudden, and might lead to a fast change in European climate patterns.