Vulnerabilities – Future storm frequency and intensity

While an overall decrease in storm frequency over northern Europe and the Mediterranean is predicted, storm frequency will tend to increase over the British Isles and Ireland (1). Storm intensity is also predicted to increase substantially as a consequence of enhanced global warming (2).

More hurricanes

Model simulations (based on a climate change scenario showing 1°C less global warming than the SRES A1B scenario) suggest that tropical hurricanes might become a serious threat for Western Europe in the future (3). An increase in severe storms of predominantly tropical origin reaching Western Europe is anticipated as part of 21st global warming. An eastward extension of the development region of tropical storms is projected. In the current climate, the main genesis region for hurricanes is confined to the western tropical Atlantic, where sea surface temperatures are above the threshold (27°C) required for tropical cyclones to develop. Future tropical storms that reach western European coasts (and cause hurricane-force storms) predominantly originate from the eastern part of the tropical Atlantic. This is because climate warming in the eastern tropical Atlantic causes sea surface temperatures to rise well above the 27°C threshold. In addition to an increase in the frequency of severe winds (Beaufort 11–12), a shift is projected of the season of highest occurrence from winter to autumn (3). Scientists stress that both natural variability and human influences (including climate change) play a role in determining the frequency, strength and trajectory of hurricanes on the Atlantic Ocean (5). 

After their formation, tropical cyclones move in a north-westerly direction. When they reach the mid-latitudes they are caught by the predominant westerly winds, thereby veering their track in a north-easterly direction, with the possibility of reaching Western Europe. Geometrically, this likelihood increases if their genesis region in the tropical Atlantic is further to the east. In addition, the shorter travel distance in the mid-latitudes will enable the “tropical” characteristics of hurricanes to be better preserved along their journey to Western Europe. Hence, the likelihood of these storms maintaining their strength when reaching Western Europe will increase, because there is simply less time for them to dissipate (4).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Ireland.

1. Environmental Protection Agency (2003)
2. McDonald et al. (1999), in: Environmental Protection Agency (2003)
3. Haarsma et al. (2013)
4. Hart and Evans (2001), in: Haarsma et al. (2013)
5. Rosen (2017)