Vulnerabilities Austria - Permafrost

Melting permafrost destabilises ground conditions. This may affect infrastructures which are placed at high altitude. Buildings, masts of cable cars, avalanche barriers etc. are vulnerable when anchored in permafrost ground (2). However, initial surveys indicate that to date the number of installations directly affected by this phenomenon is quite limited (1).

Vulnerabilities Austria - Rock fall and debris

A related problem is the frequency of rock fall and debris flows which will increase due to the combination of melting glaciers, melting permafrost, rising snow line and more intense precipitation. This may present an additional risk to climbers and hikers at high altitudes. Furthermore, the increasing threat to traffic routes from extreme events may lead to more instances where access to individual tourist resorts in the Alps is limited (1).

Vulnerabilities Austria - Buildings

The changing climate has the potential regionally to increase premature deterioration and weathering impacts on the built environment, exacerbating vulnerabilities to climate extremes and disasters and negatively impacting the expected and useful life spans of structures (3).  

Vulnerabilities Austria - Infrastructure

Small increases in climate extremes above thresholds or regional infrastructure ‘tipping points’ have the potential to result in large increases in damages to all forms of existing infrastructure nationally and to increase disaster risks (4). Since infrastructure systems, such as buildings, water supply, flood control, and transportation networks often function as a whole or not at all, an extreme event that exceeds an infrastructure design or ‘tipping point’ can sometimes result in widespread failure and a potential disaster (5).

Vulnerabilities Austria - Transport - Shipping

In Europe, the highest amount of cargo by means of inland waterways is transported in the Rhine–Main–Danube corridor. In this corridor, no decrease in the performance of inland waterway transport due to extreme weather events is expected till 2050 (9). Extreme weather events relevant to inland waterway transport are low-water events (drought), high-water events (floods) and ice occurrence. Of less importance are wind gusts and reduced visibility. There is no convincing evidence that low-water events will become significantly severer on the Rhine as well as the Upper Danube in the near future. However, on the Lower Danube, some impact of drought in association with increased summer heat might appear. Severe low-water situations seem to become more important in the period 2071–2100. A quantitative conclusion on the future effects of high water on inland waterways cannot be drawn at this stage (9).

Ice occurrence is decreasing, due to global warming, as well as human impacts leading to shorter periods of suspension of navigation in regions where navigation may be prevented by ice. In fact, the Upper and Middle Rhine navigation has not been suspended due to ice since at least the 1970s (10). For the near future (until 2050), wind gusts are expected to remain on the same level as today (11), thereby not decreasing the safety of inland waterway transport. Visibility seems to improve, if the results for European airports are considered (11), thereby improving the safety of inland waterway transport as well as operation of inland waterway vessels.

The impact of hydrological changes on navigation conditions for the Rhine-Main-Danube corridor has been studied for a number of climate change projections (for the River Rhine: 27 projections including different emission scenarios; for the Upper River Danube: 20 projections including emission scenario A1B only). Estimated changes are generally given for the period 1950 to 2050, sometimes also for the period 1850 to 2100. Four impacts were studied: low flow, floods, ice and visibility (fog) (7). The results are summarized in the table below.

Current conditions:

• Low-flow threshold: In this study, the low water threshold for navigation has been defined as the 95th percentile of the flow-duration curve for the period 1961-1990. For the River Rhine this threshold is currently (1961-1990) undershot on about 18 days per year. For the River Danube, where only monthly discharge data are available, this threshold is interpreted as the number of months the monthly 95th percentile is undershot in a 30-year period (at the gauge Vienna). Since the 1970s the number of days with discharge lower than the low-flow threshold has decreased at the Rhine gauges Kaub and Ruhrort. Beginning in the early 1990s there was a decade with only a few days below this threshold. The year 2003 was the first year of a period when longer low flow situations re-occurred. At the gauges on the River Danube similar tendencies were observed during the 20th century as on the River Rhine.
• Floods: At high water levels, navigation may be restricted in terms of speed limits, the concentration of traffic in the centre of the fairway (to reduce wave stress on the lateral infrastructure) and (at the highest threshold) a general stoppage of navigation. For both the Rhine and the Danube, neither a trend nor a tendency is obvious from the data at the studied gauges.
• River ice: With respect to the Rhine-Main-Danube corridor, ice is mainly an issue for the River Main, the RMD canal and the River Danube. Since 1950 the number of days with stoppage of navigation due to river ice has decreased.
• Visibility: Meteorological phenomena can reduce visibility and thus can harm vessels that navigate on sight. Vessels without radar systems can be stopped according to official regulations. But also vehicles with radar have to operate with care, which often means loss of time due to speed limits and slower manoeuvring. A distinct reduction of the number of days per year with low visibility has been observed at all stations in the 1970s. This may be the result of a strong decline of aerosol emissions over Europe (8).

Future conditions:

• Low-flow threshold: In this study, the low water threshold for navigation has been defined as the 95th percentile of the flow-duration curve for the period 1961-1990. For the River Rhine this threshold is currently (1961-1990) undershot on about 18 days per year. For the River Danube, where only monthly discharge data are available, this threshold is interpreted as the number of months the monthly 95th percentile is undershot in a 30-year period (at the gauge Vienna). For the near future (up to 2021-2050) all discharge projections for the Rhine except one show that the number of days below the low-flow threshold for 1961-1990 will remain in the range that has been observed since the 1950s at gauge Kaub. For the distant future (2071-2100) some projections still show a reduced number of days below this threshold, while a majority of the projections shows a higher than present number of days below this threshold. These projections show a continuation of the shift of the low-flow season from winter to summer, which has already been observed in the last decades. The low-flow situations tend to become more extreme (in terms of intensity and duration) at the end of the 21st century. For the Danube (at gauge Vienna) the majority of the projections for the near future (2021-2050) shows a moderate increase in the number of months below this low-flow threshold, whereas the distant future (2071-2100) shows that the present low-flow threshold will be undershot more frequently. The shift of the low-flow season from winter towards summer is simulated to occur in the distant future (not in the near future).
• Floods: At high water levels, navigation may be restricted in terms of speed limits, the concentration of traffic in the centre of the fairway (to reduce wave stress on the lateral infrastructure) and (at the highest threshold) a general stoppage of navigation. In this study the flood threshold for the River Rhine was defined as a discharge that is exceeded on 3% of the days per year in the mean of the period 1961-1990. For the River Danube this definition could not be applied because only monthly discharge data were available. For the near future (up to 2021-2050), most of the projections for the Rhine point towards a higher number of days than at present when navigation is restricted due to floods. Most projections are clustered in a range between 11 and 20 days per year. For the distant future (2071-2100), the span of results is much wider; also here, a majority of the projections shows more days above the threshold, ranging between 8 and more than 30 days per year. For the Upper Danube no clear picture can be given yet of the future development in the number of days with restricted navigation due to high flow.
• River ice: With respect to the Rhine-Main-Danube corridor, ice is mainly an issue for the River Main, the RMD canal and the River Danube. The number of days with stoppage of navigation due to river ice will continue to decrease. The projected reduction towards ever less restrictions for navigation due to river ice is particularly pronounced in the last decades of the 21st century.
• Visibility: Meteorological phenomena can reduce visibility and thus can harm vessels that navigate on sight. Vessels without radar systems can be stopped according to official regulations. But also vehicles with radar have to operate with care, which often means loss of time due to speed limits and slower manoeuvring. Due to current limitations of the regional climate models it is not possible to directly conclude on the number of days with fog occurrence for future time horizons. Besides, also non-climatic factors (such as effects of urbanisation) control fog formation.

Table: Summary of (projected) effects of climate and hydrological change on navigation on the Rhine-Main-Danube corridor for the second half of the 20th century (tendency 1950 to 2005), the mid 21st century (change 2021-2050 vs. 1961-1990) and the end of the 21st century (change 2071-2100 vs. 1961-1990). The findings marked by * were not directly observed or modelled but concluded from other findings (e.g. approximate indicators, neighbouring regions or from literature) (10).

Vulnerabilities Austria - Transport - Rail

In the past decade, winter consequences and flood events accounted for 96% of the total rail and road networks costs in the Alps, 92% in mid-Europe and 91% across EUR29 (EU plus Switzerland and Norway). While the road sector in mid-Europe is dominated by winter-related costs, European roads in general are slightly more affected by the consequences of floods. In rail transport, in contrast, we see a very clear dominance of floods and their consequences, including landslides, mudflows and avalanches. Floods and mass movements have a high potential for damaging infrastructures with several months of entailed repair and detouring traffic, which is more relevant in rail than in road networks as these are less dense and much more complex to operate (12).

The forecasts indicate that expected milder winters in Europe lower the expected total costs for road transport by 50%, and increase the rail-related damage costs by 80%. The latter is partly due to the high sensitivity of rail to flood and mass movement consequences and partly due to the strong increase in rail demand. Adaptation of rail networks to an increasing number of hydrological events is needed, particularly in the Alpine area (12).

Economy-wide effects of climate change impacts and adaptation to road and rail sector

Climate change increases weather-induced costs to road and rail transport. However, when roads and railway infrastructure is affected, the entire economy is affected. Because of several indirect effects to the economy, the benefits of adaptation measures should be assessed for the entire economy as well. Such a macroeconomic assessment of climate change impacts and planned sector-specific adaptation measures was made for the Austrian road and rail sector (21).

Current climate-induced direct damage costs

Current average annual weather-induced costs to the road transport sector and to the rail sector in Austria sum up to € 47 M and € 18 M per year, respectively, mostly attributable to damages to infrastructure assets. Regarding the impact categories, most of the damage is triggered by flood and rain. Other impact categories are ice and snow, storm and heat (22). The costs are two to three times larger in the road sector. When put into perspective by network length, however, damages are about 300 €/km in the road transport sector and 3300 €/km in the rail sector. Thus, damage events concerning infrastructure are eleven times costlier in the rail sector than in the road sector (23).

Climate change impacts

A doubling of current weather-induced impact costs in Austria’s land transport sectors is assumed due to climate change until 2050, based on scientific studies on the increase of extreme events (24).

Climate change adaptation

In this study, several technical and planned adaptation measures have been considered for the road and rail transport sectors to reduce climate change impacts. For both the road transport sector and the rail sector these measures include enlargement of drainage system capacities alongside roads and railroad tracks by +20%, intensification of vegetation management next to roads and railroad tracks by 20%, and an increase of transport-related expenditures of the Austrian torrent and avalanche protection agency by +50%. In addition, for the road transport sector, early warning systems improvements by installation of additional hydrological stations, and doubling of the frequency of visual road inspection are considered (21).

Economy-wide effects of climate change impacts and adaptation

The study shows that direct impact costs more than double between now and 2050 due to macroeconomic linkages: the indirect costs are larger than the direct costs. When only direct effects are captured, adaptation measures do not seem beneficial for the road sector. When indirect effects are also included, adaptation measures in both road and rail sectors clearly pay off. Adaptation leads to a net benefit at the macroeconomic level (21). 

Adaptation strategies

Climate change will require changes in building codes and standards where they exist (6).

Rail sector

In the rail sector, the ‘‘low-hanging fruits’’, namely information and communication systems, seem to have already been harvested, and investments in advanced protection systems, e.g., tunnels, protection walls and enlarged drainage, need to be considered to support proactive maintenance strategies. The currently completed, ongoing and planned rail base tunnels Simplon/Lötschberg, Gotthard and Brenner help to make the infrastructure less vulnerable to natural hazards. According to rail infrastructure experts, the most promising measures for the Alpine region are switch protection, increased (preventive) maintenance activities (infrastructure and existing protection systems), vegetation management along rail tracks and installation of (automatic) monitoring systems (12).

Adapting the urban infrastructure to reduce urban heat load

Several types of infrastructural measures can be taken to prevent negative outcomes of heat-related extreme events. Models suggest that significant reductions in heat-related illness would result from land use modifications that increase albedo, proportion of vegetative cover, thermal conductivity, and emissivity in urban areas (13). Reducing energy consumption in buildings can improve resilience, since localized systems are less dependent on vulnerable energy infrastructure. In addition, by better insulating residential dwellings, people would suffer less effect from heat hazards. Financial incentives have been tested in some countries as a means to increase energy efficiency by supporting those who are insulating their homes. Urban greening can also reduce temperatures, protecting local populations and reducing energy demands (14).

Numerous concepts have been developed to mitigate the heat load in urban areas, such as customizing urban vegetation for shading and evaporative cooling (15), introducing open water surfaces (16), planning of built structures that support ventilation by choosing an appropriate geometry and size of buildings and street areas (17), and applying suitable materials and colours for buildings to reduce the heat storage and the absorption of solar radiation (18). Increase in vegetation and water surfaces, known as green and blue infrastructure, is of particular interest due to their multiple functionality and benefits for the urban environment, such as increasing urban biodiversity and improving air quality in case of urban vegetation (19).

The cooling potential of the blue and green infrastructure to reduce the urban heat island effect has been assessed for Vienna, the capital of Austria (20). In Vienna, a warming trend has been observed between 1961 and 2010. A model simulation for Vienna with green infrastructure shows that a substantial reduction in temperature is achieved only by incorporating an extensive amount of vegetation. Heat load mitigation measures should be applied extensively in order to reach substantial reduction in urban heat load on a city scale. With the application of several heat load mitigation measures such as decrease in building density by 10% and pavement by 20%, enlargement in green and water spaces by 20%, it is possible to achieve a substantial cooling effect. A relatively small change in infrastructure may reduce the annual number of summer days with a maximum temperature ≥ 25°C by 10 or more. Temperature reduction due to implementation of green and blue infrastructure in urban areas depends on multiple factors: terrain, prevailing wind direction and wind conditions, neighbouring areas and the size of the applied measures. By concentrating the parks in the city centre, the cooling effect could be amplified as compared to locating parks in the low-density residential areas in the outer districts of the city (20). 

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 Austria.

1. Federal Office for the Environment FOEN of Switzerland (Ed.) (2009)
2. Müller et al. (2003), in: Federal Office for the Environment FOEN of Switzerland (Ed.) (2009)
3. Auld (2008b); Larsen et al. (2008); Stewart et al. (2011), all in: IPCC (2012)
4. Coleman (2002); Munich Re (2005); Auld (2008b); Larsen et al. (2008); Kwadijk et al. (2010); Mastrandrea et al. (2010), all in: IPCC (2012)
5. Ruth and Coelho (2007); Haasnoot et al. (2009), both in: IPCC (2012)
6. Bourrelier et al. (2000); Füssel (2007); Wilby (2007); Auld (2008b); Stevens (2008); Hallegatte (2009), all in: IPCC (2012)
7. Nilson et al. (2012)
8. Van Oldenborgh et al. (2010), in: Nilson et al. (2012)
9. Schweighofer (2014)
10. WSD Südwest (2009), in: Schweighofer (2014)
11. Vajda et al. (2011), in: Schweighofer (2014)
12. Doll et al. (2014)
13. Yip et al. (2008); Silva et al. (2010), both in: IPCC (2012)
14. Akbari et al. (2001), in: IPCC (2012)
15. Spronken-Smith and Oke (1998); Solecki et al. (2005); Gill et al. (2007); Memon et al. (2008); Bowler et al. (2010); Oliveira et al. (2011); Fallmann et al. (2014), all in: Žuvela-Aloise et al. (2016)
16. Hathway and Sharples (2012); Theeuwes et al. (2013), both in: Žuvela-Aloise et al. (2016)
17. Ali-Toudert and Mayer (2007a, b); Middel et al. (2014), both in: Žuvela-Aloise et al. (2016)
18. Hamdi and Schayes (2008); Krayenhoff and Voogt (2010); Santamouris et al. (2012), all in: Žuvela-Aloise et al. (2016)
19. Akbari et al. (2001), in: Žuvela-Aloise et al. (2016)
20. Žuvela-Aloise et al. (2016)
21. Bachner (2017)
22. Doll and Sieber (2010), in: Bachner (2017)
23. European Union (2012); ÖBB (2014), both in: Bachner (2017)
24. Jongman et al. (2014); Aaheim et al. (2012), both in: Bachner (2017)