Our new paper in which we reconstruct the position of the summer North Atlantic Jet over the last 300 years is out now in Nature Communications (open access): https://www.nature.com/articles/s41467-017-02699-3
We used tree rings from the Balkans and from the British Isles -two locations with climates that are strongly influenced by the position of the North Atlantic Jet (NAJ) - for our reconstruction. We find an increase of NAJ variance since the 1960s that is unprecendented over the last 300 years and that corresponds to a variance increase in climate proxies in the North Pacific ocean. Such variance increases correspond to more frequent summer NAJ extremes, which result in more frequent summer extreme weather events (floods, droughts, heatwaves, wildfires) in northwestern and southeastern Europe.
A UA press release describes the relevance of our paper in layman's terms: https://uanews.arizona.edu/story/jet-stream-changes-1960s-linked-more-extreme-weather