Reduced subseasonal variability of the North Atlantic jet stream due to climate change

The North Atlantic eddy-driven jet strongly shapes Euro-Atlantic weather and climate.  Its variability at subseasonal tiemescales is linked with regional storm tracks, atmospheric blocking, European weather and the occurrence of extreme events. However, how this variability responds to climate change has not yet been explored. Here, we use a novel jet diagnostic method to show that over the past 75 years, wintertime subseasonal variability in jet latitude and tilt has declined by 18% and 14%, respectively. Climate models indicate part of the reduction in jet variability is due to external forcing, although they tend to underestimate its magnitude. Models further project a continuous decline in jet variability throughout the 21st century under global warming. These findings reveal a robust response of the North Atlantic large-scale atmospheric circulation to climate change, and contribute to the growing body of evidence of a too low signal-to-noise in current climate models, with implications for current and future European weather predictability.