Vulnerabilities – Trends of storm frequency and intensity in the past

There is a lot of cross-border information on storms in Northern, Western and Central Europe. This information is summarized on the page for Europe in the window 'Storms'. Additional information that specifically refers to individual countries is presented on the Storm pages of these countries.

Average annual storm-related insured losses to residential buildings in Germany add up to about EUR 1.1 bn (10).

Vulnerabilities – Future storm frequency and intensity

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 (5). 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 (5). 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 (11).

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 (6).

Winter storm losses in German households

The impact of global warming on winter storm losses in the German private household sector was estimated from model projections based on the A1B scenario with focus on the period 1971–2000 for recent climate conditions, and for 2011–2040, 2041–2070, and 2071–2100 for future climate conditions (7). It was assumed that no adaptation measures were anticipated. The change in winter storm losses was expressed as the change of the so called ‘return level’ of loss amounts for an event of a certain magnitude. More precisely: for a given ‘return period T’ (say 10 years) the so called ‘return level’ is that loss ratio (the ratio between claimed loss amounts and insured values), which would occur after an average waiting time T due to an event of that magnitude or larger. Overall the results show a modest increase in return levels and shorter return periods due to global warming for Germany; these results are in line with projected changes of return periods of estimated losses for Germany and nearby countries under several SRES scenarios (9). The 10-year return values (i.e. loss ratios per return period) are projected to increase by 6–35 % for 2011–2040, 20–30 % for 2041–2070, and 40–55 % for 2071–2100. These changes are much smaller than the widths of most of the 95 % confidence intervals, however. For less frequent events, changes of return levels are of similar or larger order of magnitude as for a 10-year event (7). For Europe, current estimates of storm loss for a single 10-year storm event reach USD 7 bn (2006 prices), increasing up to USD 30 bn for events with a return level of once per 100 years (8). 

Adaptation strategies Germany

Insurance

From future projections of winter storm losses in the German private household sector it was concluded that global-warming induced increases in insured losses under the A1B scenario are generically to be expected, but can be handled within the existing insurance frameworks in Germany (7).

In Germany insurance coverance (in % of forest area) is 2% (1). Studies investigating insurance for storm damage in forests in Switzerland and Germany have shown low enthusiasm among forest owners for insurance under current economic and legal policies (2,3). The main reasons identified are the low economic importance of the forest to many forest owners and low risk awareness or rather underestimation of risks, in light of the long productivity times in forestry (2,4). The disaster relief practice of many states to compensate widely for storm damage decreases the incentive for forest owners to take their own precautions (2).

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 Germany.

1. Gardiner et al. (2010)
2. Holthausen et al. (2004), in: Gardiner et al. (2010)
3. Hänsli et al. (2002), in: Gardiner et al. (2010)
4. Schwierz et al. (2010), in: Gardiner et al. (2010)
5. Haarsma et al. (2013)
6. Hart and Evans (2001), in: Haarsma et al. (2013)
7. Held et al. (2013)
8. Schwierz et al. (2010), in: Held et al. (2013)
9. Donat et al. (2011a); Pinto et al. (2012), both in: Held et al. (2013)
10. GDV (2012), in: Held et al. (2013)
11. Rosen (2017)