A new report conducted by researchers at the University of Exeter offers insight into why Northwest Europe experienced extraordinarily wet summers between 2007 and 2012, stating that melting sea ice and changes with the jet stream are to blame for these soggier summers. Jet streams are currents of strong winds high in the atmosphere that steer weather systems and their rain. Normally in summer the jet stream lies between Scotland and Iceland and weather systems pass north of Britain. However, the jet stream has shifted south in recent summers, bringing unseasonable wet weather to Britain and northwest Europe. The cause for the jet stream shift is being attributed to the loss of Arctic sea ice.
A new report conducted by researchers at the University of Exeter offers insight into why Northwest Europe experienced extraordinarily wet summers between 2007 and 2012, stating that melting sea ice and changes with the jet stream are to blame for these soggier summers.
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Jet streams are currents of strong winds high in the atmosphere that steer weather systems and their rain. Normally in summer the jet stream lies between Scotland and Iceland and weather systems pass north of Britain. However, the jet stream has shifted south in recent summers, bringing unseasonable wet weather to Britain and northwest Europe.
The cause for the jet stream shift is being attributed to the loss of Arctic sea ice.
Dr James Screen from Mathematics at the University of Exeter used a computer model to investigate how the dramatic retreat of Arctic sea ice influences the European summer climate. He found that the pattern of rainfall predicted by the model closely resembles the rainfall pattern of recent summers.
Dr Screen said: "The results of the computer model suggest that melting Arctic sea ice causes a change in the position of the jet stream and this could help to explain the recent wet summers we have seen. The study suggests that loss of sea ice not only has an effect on the environment and wildlife of the Arctic region but has far reaching consequences for people living in Europe and beyond."
The model suggests that while summer rainfall increases in northwest Europe, Mediterranean regions will receive less rain. The effects are not limited to Europe - weather systems as far as North America could also be influenced.
The study compared weather patterns during low sea ice conditions as seen in recent years to weather patterns during high sea ice conditions typical of the late 1970s. The results suggest that if sea ice loss continues as it has over recent decades, the risk of wet summers may increase.
Other studies have suggested that recent ocean warming of the North Atlantic could also be responsible for more summer rain in northwest Europe. It is likely that several other factors, combined with the impact of melting Arctic sea ice, explain the recent run of wet summers.
The paper is published in Environmental Research Letters.
Read more at the University of Exeter.
Arctic ice image via Shutterstock.
