Impacts of Climate Change
Climate change-induced temperature changes affect transport infrastructure and road users and can endanger transport safety. In particular, this applies to the increasing temperatures in the summer, combined with heatwaves. However, larger temperature jumps are also relevant such as individual hot days in spring. These are even more serious for the infrastructure than permanently high temperatures.
High temperatures can cause material and structural damage to road surfaces and rails. For example, some road surfaces become softer, which can cause ruts from heavy traffic. Rails expand at high temperatures, which can lead to track distortion. Heat-induced failures can also occur in the control and safety technology. On motorways, roads are often closed as a result of 'blow-ups', which repeatedly occur when the concrete slabs of older motorways expand in the heat and suddenly buckle due to the resulting stresses.
Heatwaves combined with drought increase the risk of vegetation and embankment fires along tracks and roads and are expected to become more frequent in the future. In addition, increasing temperatures pose a health risk as they affect the ability of road users and passengers to concentrate and react. There is an increasing risk of accidents.
On the other hand, traffic disruption due to frost, snow and ice may decrease with climate change, as fewer days of frost are expected overall. This means, for example, that the icing of inland waterways and airplanes could occur less frequently and that shipping and air traffic will be less affected in the long term because of the reduction in the number of frost days.
However, frequent switches between frosty and non-frosty days wears out rails and road surfaces. This can shorten the renovation cycle of transport infrastructure constructions.
In recent years, heavy rainfall events have been observed practically throughout Germany. Climate researchers expect that the frequency of heavy rainfall and its intensity will generally increase in the future.
Increasing heavy and continuous rainfall can lead to flooding of various kinds, resulting in the flooding and undercutting of transport infrastructure, thus impairing the flow of traffic. Straight underpasses and tunnels are at risk and the risk of road accidents due to aquaplaning can increase.
Traffic control systems such as traffic lights and signals can also be damaged by flooding and inundation. The undercutting of traffic routes can reduce the stability of railroad embankments, track beds and roads. At the same time, they also affect soil stability and could trigger landslides that damage the transport infrastructure.
Last but not least, heavy rain also impairs driving safety and punctuality on roads and rails. For example, sudden heavy rainfall significantly reduces the visibility of road users. Between 5% and more than 20% of the federal motorways are affected by level 3 heavy rainfall warnings every year.
In case of floods (e.g. due to increased precipitation in the winter months) inland waterway transports may have to be suspended.
Too little precipitation and drought also restrict inland shipping. In recent years, low water levels in Germany during the summer have already repeatedly hindered or even interrupted navigation in some rivers. Low water levels can also mean that ships can no longer be fully loaded. With increasing global warming, summer low water level situations are expected to worsen.
The restrictions on inland waterway transport can have a significant impact on individual companies or entire production and supply chains. These can range from increased transport costs to production downtime in companies with just-in-time production.
Other extreme weather events
It is currently still unclear how climate change will affect storms, thunderstorms and hail. Storms with thunderstorm activity and lightning can cause failure of or damage to signals and other electronic traffic control systems. High-rise installations such as overhead contact lines and traffic signs are naturally particularly sensitive to storms. However, strong winds can also endanger and disrupt traffic by blowing branches and other objects onto roads and rails.
In recent years, dust and sandstorms have also caused accidents in some regions. With increasing soil dryness in the summer, these could occur more frequently in the future.
Changes in sea level
The rise in sea level and storm tides are a problem especially for shipping as harbors and maritime constructions are heavily burdened or even damaged. Sea level rise and storm tides can also affect land transport when railway lines and roads are damaged or have to be relocated.
Adaptation to Climate Change
Transport systems and the associated infrastructures are classified as critical and are considered highly complex and sensitive. They are of great importance for the functionality of society. For their protection and preservation, technical adaptation measures for climate change are considered particularly relevant to prevent damage. This also requires the overall adaptation of planning and construction standards.
Technical measures for dealing with high temperatures may include the use of heat-resistant asphalt mixtures that prevent 'blow-ups'. In addition, continuously welded rails and improved cooling of the electronic components of infrastructures, such as control and safety technology in rail traffic, can be technical adaptation measures. On the other hand, investments to protect against the icing of switches or roadways could be reduced in the future due to the expected reduction of frost days.
In order to prevent damage caused by heavy rainfall events, especially flooding and undercutting, the planning and dimensioning of drainage systems must be adapted. This concerns drainage and pumping systems for tunnels, bridges and roads. In areas at risk of landslides, slope stabilisations can protect individual sections of the road during heavy rainfall. Risks caused by stagnant water on roads can be avoided by milling out ruts or adapting the road layout, for example.
To adapt for storms, bridge design can be adapted to improve the connection between the carriageway and the foundation structure, for example. This requires building materials with increased stability. In addition, protective walls along roads and railways can contribute to prevention.
Rising sea levles can also endanger coastal transport infrastructure. Here it is advisable to consider relocating routes and plan alternative routes, as well as to orient investments in ports accordingly.
Ecosystem measures (especially "vegetation management") also play a role in the adaptation of transport infrastructure to the impacts of climate change. When dealing with strong wind events and storms, the adaptation of tree species and vegetation composition along routes can help to reduce the risk of falling trees. Stronger vegetation control can help to prevent slope fires.
Moreover, larger aisles without planting can help in both cases.
However, a conflict of objectives can arise here, since the vegetation along roads and railways fulfils the important function of shading, which plays a decisive role in protecting traffic routes and vehicles from overheating. Healthy protective forests also shield vehicles from squalls.
The risk of flooding and undercutting of transport infrastructure from heavy rainfall and high water levels can be limited by providing sufficient flood plains along rivers and in coastal regions.
Legal, political and management measures
Legal, political and management measures support the adaptation of the transport sector to the consequences of climate change in three areas: in planning (new construction), in the existing infrastructure (preventive) and when dealing with weather damage (subsequent). Since both the private and public sectors are responsible for transport infrastructure, responsibilities and tasks must be distributed appropriately. Since 2016, the network of experts from the Federal Ministry of Transport and Digital Infrastructure (BMVI) has been conducting in-depth research to enable climate resilient and environmentally-compatible modes of transport through innovation.
Individual modes of transport face particular challenges. In particular, the maritime industry needs to expand monitoring, forecasting and warning services and adapt risk management and technical requirements for ships and port infrastructure. This is because storms and heavy seas are becoming more likely as a result of climate change. With regard to inland navigation, adaptation to possible low water levels in the maintenance of waterways is necessary through sediment management, for instance. In addition, shipping companies can use smaller ships with less draught at low water.
The public sector is also called upon to revise guidelines and regulations. This includes guidelines for disaster management, emergency rescue, construction and planning decisions and other norms and standards. Improved communication and cooperation between industries, associations and authorities is important.
Organisational measures can also help to adapt the transport sector:
- Monitoring of damages
- Risk and impact analysis for the infrastructure portfolio
- Risk mapping for extreme weather events
- Preparation for failures
- Reduction of intervals for maintenance and servicing
- Replacement of damaged traffic infrastructure with climate-resilient alternatives
- Climate resilient planning of new transport infrastructure
Improved communication can also raise awareness of the problem among all actors and road users, thus increasing personal provision and the acceptance of adaptation costs.