Vulnerabilities - Global assessment rail and road infrastructures

Selected scenarios

The exposure of global rail and road infrastructures in future record-breaking climate extremes was assessed for six major infrastructure types: railway, motorway, trunk, primary road, secondary road, and tertiary road. Several General Circulation Model projections were used for this, based on four climate change scenarios ranging from an optimistic to a pessimistic scenario. Selected future projections are mid-21st century (2031–2060) and late-21st century (2071–2100) and the historical record for comparison is 1950–2014 (62).

Selected hazards (indicators)

Eight indicators closely related to rail and road infrastructure safety were selected, involving extreme temperatures and precipitation. For extreme temperatures, four indicators – maximum temperature, thaw-freezing index ratio, annual temperature difference, and annual freeze-thaw cycles – were selected to describe extreme heat, intensity and frequency of freezing, annual highest and lowest temperature span, and the frequency of freeze-thaw cycles, respectively. For extreme precipitation, four indicators – annual precipitation, maximum daily precipitation, annual torrential rain days, and annual drought and heavy rain compound event – were selected to describe the environmental wetness level, the intensity and frequency of extreme precipitation weather, and the frequency of heavy rain occurring in drought months, respectively (62).

Results

The results of this assessment suggest that higher extreme heat and increasing thaw-freezing index ratio pose great threats to global rail and road infrastructures. The expected global annual exposures of these two hazards are 4 and 2 times the average exposure level of the eight hazards (indicators), respectively (62).

Vulnerabilities - Assessment 571 European cities

Over 75% of the population of the European Union lives in urban areas, and this percentage is expected to grow to 82% by 2050 (30). Needless to say it’s important to know how droughts, heat waves and floods in Europe’s cities will change. This has been assessed for 571 European cities under a high-end scenario of climate change (RCP8.5). The results are based on 50 climate model projections. Changes refer to the future period 2051 – 2100 in comparison to the historical period 1951 - 2000 (29).

Heatwaves

In this study heat waves are defined as three consecutive days where both maximum and minimum temperature exceed the upper 5% of these values for the historical period. According to the results all European cities will experience more frequent and hotter heat waves. The cities in Southern Europe see the largest increase in the number of heat wave days, possibly up to 69%. Projected increase of maximum temperature during heat waves is largest in central European cities, however, even up to 14°C (for Innsbruck in Austria). In this part of Europe both infrastructure and populace are generally not adapted to extreme heat (29).

Droughts

The severity of a drought is defined in this study as the accumulated precipitation deficit relative to mean annual rainfall. Southern European cities will see an increase in drought conditions: future droughts may get up to 14 times worse than the ones in the historical period. To a certain extent this region may be adapted to drought. The projected upper level of change is likely to be beyond breaking point in many cases, however (29). This supports recent analysis of the potential for a mega drought in major Iberian water resource regions (31). For mid and northern latitude cities it is very unlikely that droughts will get much worse than the ones in the historical period.

Floods

In this study a flood is defined as the maximum discharge that occurs on average once every 10 years. Floods were only considered for cities with a river that has a catchment area of at least 500 km2. Increases in river flooding are most prevalent in north-western Europe, and are particularly worrying for the British Isles and several other European cities which could observe more than a 50% increase of their 10 year high river flow (29). One should be aware, however, that snowpack and melting processes are not accounted for in this study; this may affect the results for Scandinavian and Alpine cities.

Cities most at risk

Capital cities that are among the top 100 for one or more hazards according to this study, are Dublin, Helsinki, Riga, Vilnius, and Zagreb for river flooding, Stockholm and Rome for the increase of number of heat wave days, Prague and Vienna for the increase of maximum temperature during heat waves, Lisbon and Madrid for droughts, and Athens, Nicosia, Valleta and Sofia for both the number of heat wave days and the severity of droughts (29). 

Vulnerabilities - 'Critical infrastructures'

Vulnerability of ‘critical infrastructures’

Infrastructures are ‘critical infrastructures’ when they are vital to ensure health, wealth, and security. They include existing transport systems, energy generation plants, industry, water supply networks, and education and health infrastructures. The impacts of climate change may damage these infrastructures. For the European Union plus Switzerland, Norway, and Iceland (EU+), this was assessed for the seven most harmful climate-related extremes: heat and cold waves, droughts, wildfires, river and coastal floods, and windstorms. The analysis is carried out for 2011 – 2040 (the 2020s), 2041 – 2070 (the 2050s), and 2071 – 2100 (the 2080s) under a moderate scenario of climate change (the so-called A1B emissions scenario); 1981 - 2010 is used as the reference period (27).

Overall risks for Europe

According to this assessment damages to ‘critical infrastructures’ in the EU+ could triple by the 2020s, multiply six-fold by mid-century, and amount to more than 10 times present damage of €3.4 billion per year by the end of the century due only to climate change (all future damages are expressed in 2010 euros). Damage from heat waves, droughts in southern Europe, and coastal floods shows the most dramatic rise, but the risks of inland flooding, windstorms, and forest fires will also increase in Europe, with varying degrees of change across regions. Economic losses are highest for the industry, transport, and energy sectors. Southern and south-eastern European countries will be most affected and, as a result, will probably require higher costs of adaptation (27).

Most-affected sectors: Energy, Transport and Industry

The strongest rise in multi-hazard damage is projected for the energy sector. Current (expected annual) damage of €0.5 billion per year could be 400%, 860% and 1600% higher by the 2020s, 2050s, and 2080s, respectively. This rise results from the sectors sensitivity to droughts and heat waves (e.g. decrease in cooling system efficiency of power plants due to higher water/air temperature) (27).

A comparable trend can be observed for the transport sector: an increase of current damage of €0.8 billion per year with 1500% by the end of this century. For the transport sector, heat waves will largely dominate future damage (92% of total hazard damage by 2080s), mainly by affecting roads and railways (e.g. buckling of rails, melting of asphalt). Inland waterway transport will increasingly be affected by droughts (e.g. less navigation capacity due to low water levels in rivers). Sea level rise and increased storm surges will lead to strong increases in damage to ports in the coming century (27).

For industry, which faces the greatest damage among the sectors considered, current damage of €1.5 billion per year is estimated to increase 10-fold. Floods and windstorms currently dominate hazard losses in the industry sector, mainly through structural damage to infrastructures, machinery, and equipment. Although flood and windstorm damage is on the rise, those of droughts and heat waves will quickly outweigh its contribution in the coming decades. The impacts relate mostly to the degradation of water quality and a reduction of the decomposition rate of water and waste management systems, with corresponding higher costs for water and its treatment (27).

The impacts of most-destructive hazards

Whereas current multi-sector hazard damage relates mostly to river floods (44%) and windstorms (27%), the proportions of drought and heat waves will rise strongly, to account for nearly 90% of climate hazard damage by the end of the century (compared with 12% in 1981 - 2010). The relative contributions of wildfires and coastal floods to the overall projected damage are low, despite the strong increase in coastal flood damage that is projected for the coming century. Reported cold-related damage in Europe is marginal and could completely disappear with global warming (27).

Differences across Europe

The increase in damage load will be strongest in southern Europe, with the most southerly regions progressively more prominently affected by future climate extremes than the rest of Europe. A large part of the north-south damage gradient across Europe relates to droughts, which will strongly intensify in southern parts of Europe and become less severe in northern regions (28). For the energy and industry sector, being especially sensitive to this hazard, damage will strongly increase in the south and decrease in the north of Europe. River and coastal floods will remain the most critical hazard in many floodplains and coastal stretches of western, central, and eastern Europe, including the British Isles, Poland, the Czech Republic, Bulgaria, Romania, and northern coastlines of the Iberian Peninsula (27).

Cost of adapting infrastructures to climate change

Investments to make these critical infrastructures resilient to the changing climate up to 2040 are estimated to equal €25 billion. For climate change in the medium term (up to 2070) the estimated investments for adaptation equal €87 billion, and for the end of the century over €200 billion. In addition, maintenance costs will rise as well. Adaptation costs will not fall equally across Europe (27). 

Vulnerabilities - More extreme events

Infrastructure resilience for future rainstorms

Climate change impact on extreme precipitation in Europe calls into question the resilience of the existing infrastructure under more frequent and intense rainstorms in the future. Europe’s infrastructure is designed to withstand extreme rainfall conditions up to a certain level. Now that these conditions are changing, and the frequency of high rainfall intensities is increasing, the design criteria of the past need to be adjusted as well. A study for the entire European continent has been carried out to see how projected changes in extreme rainfall feed into design criteria for infrastructure (53).

The intensity of extreme precipitation in the area where you live, in mm’s rainfall per hour, is higher for shorter than for longer time intervals. When it rains, say, for 24 hours in a row, there will be a period of 1 hour when it rains hardest. Likewise, there will be a period of two hours when it rains a little less hard than that one-hour period, but harder than the average for the entire 24 hours period. And so on. In other words: when you plot rainfall intensity against the duration of rainfall, the curve in the graph will be a decrease of rainfall intensity with an increase of rainfall duration. This is a ‘rainfall intensity-duration’ curve.

You can draw-up such a curve for rainfall events that happen annually. Likewise, you can make these curves for rainfall events that happen once every two years, every ten years, or once in a hundred years. These curves will not be the same. Rainfall intensity during a certain time interval, say an hour, will be more extreme when the events you look at are rarer (and the frequency of occurrence is smaller). Maximum rainfall intensity for one hour will be higher for rainfall events that happen only once a decade compared with rainfall events that happen annually.

So, when you plot ‘rainfall intensity-duration’ curves for an annual event and a decadal event in the same graph, the curve for the decadal event will take a higher position in the graph, indicating higher rainfall intensities on the vertical axis for the range of rainfall durations on the horizontal axis. By including the effect of frequency of occurrence of rainfall events, we get ‘rainfall intensity-duration-frequency’ curves.

We use these curves when designing our roads, railways, bridges, etc. These curves tell us what extreme rainfall conditions our infrastructure needs to withstand. If we want our infrastructure not to be destroyed under rainfall conditions that happen more often than once a century, we take the ‘rainfall intensity-duration’ curve for a return period of 100 years as a starting point for our design.

Rainfall intensity is increasing in Europe because of climate change. The ‘rainfall intensity-duration’ curve for a return period of 100 years is different now than it was 50 years ago, and it will continue to change in the future. This change calls into question the resilience of the existing infrastructure under more frequent and intense rainstorms in the future. The infrastructure has been designed for less extreme conditions than we have today. The risk of infrastructure breaking down will increase unless we adapt them to the more extreme rainstorms of the future (53).

If we want to adapt our infrastructure to the more extreme rainstorms of the future, we need to know how these curves are changing. This has been studied for Europe as a whole. Curves have been quantified for rainstorms with different return periods ranging between 1 and 100 years. For each return period, rainfall intensity has been quantified for several rainfall durations: 0.5, 1, 3, 6, 12 and 24 hours. This has been done for the period 1971-2000, representing current conditions, and for two future time slices: 2041-2070 and 2071-2100. The curves for current conditions have been quantified from satellite data verified with ground-based observations. The curves for future time slices have been quantified from climate model projections for a moderate (RCP 4.5) and high-end scenario of climate change (RCP 8.5) (53).

Extreme precipitation events will intensify this century. This intensification will be larger for rarer extreme events compared to less rare events, in agreement with earlier studies (54). The intensification will also be larger for shorter duration events compared with large duration ones. According to this study, sub-daily extreme precipitation intensities that now occur once every 50 or 100 years, will occur two to three times as often by the end of this century for a moderate and high-end scenario of climate change, respectively. So, return periods of extreme events will be much lower. The curve that shows rainfall intensity at different rainfall duration for, say, once-in-a-hundred years events will be different mid-century and even more so by 2100 compared with current conditions. These curves will also be more different for a high-end scenario of climate change compared with a moderate one (53).

The scientists state that these results call into question the resilience of the existing infrastructure under more frequent and intense rainstorms in the future. Proper adaptation strategies are needed to reduce the breakdown risk of infrastructure designed based on historical rainstorms, and create resilient societies, they conclude (53).

More frequent heavy precipitation events

Future change in frequency, size, duration, and severity of heavy precipitation events in different parts of Europe was estimated from simulations with a large number of climate models (GCMs and RCMs) for an intermediate (RCP4.5) and high-end (RCP8.5) scenario of climate change. The study focused on rain events with a current 10-year return period of occurrence: from interviews with infrastructure providers, emergency rescue services, and private weather services it was concluded that the 10-year return period of rain events is a good threshold for the detection of relevant events. Changes were studied for future time-slices 2021-2050 and 2071-2100 compared with 1971-2000 as a reference (18).

According to this study, all over Europe the frequency of sub-daily (lasting for 3 hours), daily (24 hours), and multi-day (48-72 hours) heavy precipitation events will increase this century. Projected increase is highest for sub-daily events: in the high-end scenario of climate change the frequency of heavy precipitation events may increase from once every 10 years by more than 300 % to once every 2-3 years. For most of Europe, the frequency of daily and multi-day heavy precipitation events is projected to increase by up to 150 %; an exception is the western Mediterranean region where the number of daily and multi-day events seems to decrease (18).

The results also suggest that the areas affected by heavy precipitation events may become larger in many European regions, especially for sub-daily events. This can have consequences for infrastructure networks. Larger-scale events may damage more infrastructure elements at the same time, and more personnel may be needed for repairs and emergency services. In addition, larger events are more likely to cause river flooding. The results of this study do not clearly indicate whether on average heavy precipitation events become stronger. The strongest precipitations events were detected in the future time slices, however, suggesting that infrastructure providers may have to cope with unprecedented events in the future. The climate change simulations do not show changes in event duration (18).

Currently, the frequency of heavy precipitation events is highest over (parts of) Iceland, western Norway, the Alps, north-western Spain and the Mediterranean coast, for both sub-daily, daily, and multi-day events. Except for the Mediterranean coast these are also the regions where the projected increase of heavy precipitation events is highest: the westward-facing sides of the European coasts (western Scandinavia, western Ireland, western Scotland, Iceland, the western Balkans). Under a high-end scenario of climate change, for these regions daily and multi-day heavy precipitation events with a 10-year return period may become twice as likely, and sub-daily events even three times as likely by the end of this century, for all seasons. Compared with this high-end scenario, the simulated changes until the end of the century are a little less under a more moderate scenario of climate change: 60 % for daily and multi-day, and 75 % for sub-daily events (18). 

Damage costs of extreme events now and in the future

During 1998-2010 the total annual weather-inflicted damage costs across all transport modes (road, rail, aviation, inland navigation and maritime shipping), weather categories and European regions were estimated to be €2.5 billion (4). These costs refer to very extreme events only; damage estimates might be 10 times higher when all adverse weather conditions are considered (4). The indirect costs, such as production losses due to delayed or cancelled deliveries or business trips or damages of cargo, have been estimated to amount an additional 20% (5). A 20 % increase of these costs is estimated until the period 2040-2050, including all transport modes and logistic, with the sole exception being urban public transport (20). The most affected transport mode in Europe is road transport, which bears ca. 80% of total costs, followed by air (16%) and rail transport (3%). Infrastructure assets and operations account for the highest losses: 51% of total costs (43% asset and 8 % operations) followed by users’ costs (delays and accidents). Severe winters and floods have the largest impact on the transport system, with winters accounting for 43% of the costs and floods 39% (4).

The costs of €2.5 billion are largely due to road traffic. However, broken down to passenger and ton kilometers the highest risk is borne by rail traffic due to its expensive infrastructures and its comparably complex operating structure. This indication even amplifies when looking at 2040–2050: while average road transport costs will only rise by 7% due to milder winters, rail traffic costs may increase by up to 80% due to more floods and less predictable winter periods. These results are highly uncertain, however (4). According to other estimates the impact of climate change on road and rail transport in 2050 in terms of welfare loss as a percentage of GDP is negligible (below 0.1 %), and much lower than the impacts on other sectors, such as water or health (21).

Under a moderate scenario of climate change (the so-called A1B scenario) total damages to road and rail networks due to extreme precipitation were estimated to be EUR 930 million/year by the end of the century. This is an increase of about 50% from the current baseline damages of EUR 629 million/year) and EUR 770 million/year under a 2 °C warming scenario (22). 

Vulnerabilities - Differences among transport modes

Aviation

Clear-air turbulence is high-altitude aircraft bumpiness in regions devoid of significant cloudiness and away from thunderstorm activity. It is invisible and cannot be foreseen by pilots or on-board radar. The aviation sector relies on operational turbulence forecasts produced by numerical models. Without warning, an aircraft can be violently thrown about by this turbulence, and unsecured objects and unbuckled passengers and crew can be tossed around the cabin, causing serious injuries and even fatalities (24). Clear-air turbulence has been found to account for 24% of weather-related accidents (25) and turbulence more generally for 65% of weather-related accidents (26).

Clear-air turbulence has increased over the past four decades, consistent with the expected effects of climate change (65).

According to studies based on the latest climate models, climate
 change will increase clear-air turbulence (23). The largest increases are projected for the mid-latitudes in both hemispheres. Under a high-end scenario of climate change (RCP8.5), focused on the future period 2050-2080, some regions may experience several hundred percent more turbulence. The busiest international airspace experiences the largest increases, with the volume of severe clear-air turbulence approximately doubling over North America, the North Pacific, and Europe under this high-end scenario. Over the North Atlantic, severe clear-air turbulence in 2050-2080 may become as common as moderate turbulence in the past. These results highlight the increasing need to improve operational forecasts of this turbulence and to use them effectively in flight planning, to limit discomfort and injuries among passengers and crew (23).

These findings may have implications for aviation operations in the coming decades, the authors of this study conclude. Many of the planes that will be flying in the second half of this century are currently in the design phase. Airframe manufacturers should prepare for a more turbulent atmosphere, even at this early stage, and operational clear-air turbulence forecasts should be improved (23). 

Road and rail transport

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 (6).

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 (6).

In addition to infrastructure damages, downpours/floods may also result in an increase in rain-related road accidents (due to vehicle and road damages, reduced vehicle traction and poor visibility), delays, and traffic disruptions (41). 

Climate Change impacts on roads throughout the twenty-first century

Amongst others, the following damages can occur: track and line side equipment failure; flood scours at bridges and embankments due to high river levels and culvert washouts; flooding of below-grade tunnels; obstructions of railway tracks and embankments, bridges and culverts; landslides, mudslides and rockslides; and, problems associated with personnel safety and the accessibility of fleet and maintenance depots (40). 

Damages associated with rutting, blow-ups, and landslides cause substantial budget spending on maintenance, repair, reinforcement, and design work. An assessment of these impacts was carried out for cold winters in Northern Europe (Scandinavia and the Baltic States), for hot summers in the South (Iberian Peninsula), and for extreme weather events in Central Europe (34).

Future changes in the North and the South of Europe were addressed by using global climate models, and a moderate and high-end scenario of climate change (the so-called A1B and A2 scenarios). Future changes in Central Europe were addressed by downscaling the global model projections with regional climate models, thus allowing for more geographical detail; this was done for the moderate scenario of climate change only. Projections were made for two future periods: the near future (2021 - 2050) and the remote future (2071 - 2100) (34).

Northern Europe: Classic winter maintenance work in Northern Europe includes snow and ice clearance, spreading salt, and mending cracks and bumps in roads caused by frost, falling rocks and frost heave. This work will become less important along with climate change, but other threats may appear. Ground stability at higher altitudes will decrease, causing falling rocks and landslides at altitudes that have not been jeopardized by such threats so far (34).

Southern Europe: Summer road damage mending programs are common in the South. Climate change will considerably enhance pressure on already carried out maintenance, repair, reinforcement, and adaption work. Rutting of asphalt pavements and blow-ups of concrete roads are linked to heat waves. Roads are particularly prone to rutting and blow-ups if heat waves are made up of uninterrupted successions of hot days with air temperature over 30 °C intersected by tropical nights with temperatures over 20 °C. These conditions hamper the cooling of roads and hence promote the accumulation of heat energy in road surfaces (34).

Central Europe: Landslides, rutting, and blow-up events in Central Europe will occur more frequently throughout the twenty-first century, and will impact Central European transport infrastructure more severely than in the past. The study shows that already in the near future, landslide-triggering events will increase over the entire region. Some areas stand out: the Schwarzwald area, the Schwäbische Alb, the pre-Alps in Bavaria, the foot- hills of the Austrian Alps, the Böhmerwald region northwards to the Fichtelgebirge, and the Erzgebirge. Across these areas, on average, up to six more landslide-triggering climate events may occur annually, compared to the current situation (34).

For most regions in Central Europe, the occurrence frequency of weather conditions that may lead to rutting/blow-up events will increase only slightly in the near future. In the remote future period, however, these weather events are projected to occur substantially more often, on average up to about seven days per year. The spread in the model results is quite large, indicating that this frequency may even be up to 20 days per year at the end of this century (34).

In general, the regions where landslides are projected to occur more frequently show relatively little increase in the frequency of rutting/blow-up events. This may be related to topography: high-intensity precipitation events, leading to landslides, are often related to mountainous areas, while high temperature conditions occur more frequent at lower altitudes (34).

All risks to transport infrastructure are increasing: All analyzed risks to transport infrastructure are found to increase over the decades ahead with accelerating pace towards the end of this century. In Central Europe, this acceleration is more obvious for rutting and blow-ups than for landslides. In Northern Europe, winter temperatures increase with less pace than summer temperatures in the Iberian Peninsula (34).

Climate Change impacts on railways throughout the twenty-first century

River floods can cause substantial damage to Europe’s railway infrastructure. In the period 1970 - 2005, the estimated average damage to railway tracks in the European Union (plus Norway) from river flooding was €581 million per year (spread ranging from €403 million to €801 million). This is about 11 – 14% of overall annual river flood losses in the EU. Flood risk to railway infrastructure in this period was highest in Germany (165 million annually) and France (106 million), followed by Spain, Sweden, the Czech Republic, Italy, and the UK. This risk could increase substantially due to climate change: by up to 310% under a 3 °C warming scenario, according to recent estimates (35).

Future flood risk to railway infrastructure in the European Union has been estimated under different scenarios of global warming, using an infrastructure-specific damage model. Climate model projections from several global models were used for this. Flood risk was assessed for three levels of global warming: 1.5 °C, 2 °C, and 3 °C above preindustrial levels. Damage estimates reflect the 2015 price level; differences between countries in terms of repair costs were accounted for (35).

Current risk to railway networks is projected to increase by 255% under a 1.5 °C, by 281% under a 2 °C, and by 310% under a 3 °C warming scenario. Largest risk increases (under a 3 °C scenario) are projected for Slovakia, Austria, Slovenia, and Belgium. Compared with the 3 °C scenario, limiting global warming to the 1.5 °C and 2 °C targets of the Paris Agreement would result in annually avoided losses of €317 million and €164 million, respectively (35). To cover the risk increase due to climate change, European member states would need to increase expenditure in transport by €1.22 billion annually under a 3 °C warming scenario without further adaptation (35).

There are some relevant limitations to this assessment. Only flooding from rivers and streams was considered; flooding was assumed to occur when precipitation leads to discharge conditions that exceed the current protection standards of these rivers and streams. In these projections, the present railway infrastructure assets were kept constant, and only damage to railway tracks was included; damage to railway stations, control centers, or bridges was excluded from the analysis. Also, indirect losses caused by disruptions of train traffic were not included (35).

Inland navigation

Inland waterways can be affected by both floods and droughts. Floods can have major impacts such as the suspension of navigation, damage to port facilities due to increased loads on structures, damage of banks and flood protection works (42), silting, changes in the river morphology (43).

As far as inland waterway transport is concerned, low water level situations have the highest impact: low water conditions can generate problems for passage of (mainly) larger freight ships for longer periods of time, reducing their loading capacity. A case study on the Rhine–Main–Danube (RMD) corridor has found that the average annual losses due to low water levels were about € 28 million over a period of 20 years (44). Projections from different climate models, however, did not show significant impacts on the RMD corridor by low flow conditions until 2050; nevertheless, ‘dry’ years might lead to a 6 - 7 per cent increase in total transport costs compared to ‘wet’ years (40). For the case-study of the Rhine canal and the Rhine–Main–Danube canal no significant effects on low-flow conditions until 2050 are projected. Drier summers and wetter winters only gain importance toward the end of the century (2).

For all ship sizes, the transport costs will probably increase with decreasing water depths. At low fairway depths, the benefit of large-sized ship becomes a disadvantage; the operating costs of large vessels at low water depths increase at a much stronger rate than those of smaller vessels. Under the projected climate impact until 2050, it is unclear whether the improvements in ship carrying capacity while operating a large vessel outweigh its higher vulnerability during dry periods (2).

Ports

Over 60 per cent of the European Union seaports may be under high inundation risk by 2100 under a sea-level rise of 1 m and extreme sea levels (including the effects of storm surge and extreme waves) of about 3 m (45). Impacts could include disruptions to operations and damages to port infrastructure and vessels, which will also affect hinterland connections. Seaports in Greece, the United Kingdom and Denmark will be affected by 2080, when the number of European Union seaports facing inundation risks is expected to increase by 50 per cent relative to 2030 (852 ports). This trend is particularly noticeable along the North Sea coast, where over 500 ports with traffic accounting for up to 15 per cent of the world’s cargo transport are situated (46).

Energy infrastructure

Sea-level rise and extreme events have the potential to significantly impact coastal energy infrastructure through flooding and erosion. Coastal energy infrastructure includes oil refineries, gas processing facilities and storage, liquid natural gas (LNG) plants and terminals, tanker terminals, ports, nuclear power stations, mining facilities and wind farms (1).

There are 158 major oil, gas, LNG and tankers on the European coast, along the 112,000 km coast from the Norweign/Russian Federation border to the Turkish/Syrian border, including the UK and Ireland. These facilities comprise 62 oil terminals, 12 gas terminals, 19 LNG terminals and 65 tanker terminals. 40 % of the total facilities are around the North Sea (1).

Located in 13 coastal European countries, 71 out of the 191 operating nuclear reactors (37 %) and 28 out of 72 locations (38%) are coastal. Many of the reactors are located in northern Europe with a particularly heavy concentration of reactors along the French and British coasts. The UK has three times as many coastal facilities than any other European country (1).

Opportunities - Trans-Arctic shipping

There are also benefits to climate change. One of them is the increase of possibilities to use the Arctic sea for trans-Arctic shipping routes. Due to the reduction in summer Arctic sea ice the Arctic Ocean can be used as a shortcut between Pacific and Atlantic ports for increasing (summer) periods in future decades (12).

When these routes cannot be used, sailings from Europe and North America to East Asia currently go via the Suez Canal and the Panama Canal, respectively. These sailing routes currently take 30 days for routes between Europe and Asia (from Rotterdam to Yokohama) and 25 days for routes between North America and Asia (from New York to Yokohama) (12). Trans-Arctic shipping routes substantially reduce the sailing distance compared with Suez and Panama Canal routes, and could result in large cost savings due to reduced fuel consumption and increased trip frequency (13). Shorter shipping routes also have the potential to reduce global shipping emissions (14). European trans-Arctic voyages may take as little as 17 days, and North American voyages may take only 20 days (12).

The impact of Arctic sea ice decline on trans-Arctic shipping has been assessed for several global climate model simulations, and low-end, medium and high-end scenarios of climate change (the so-called RCP2.6, RCP4.5, and RCP8.5 scenarios). Transit conditions are optimal around September. Open water vessels (with no specific ice strengthening) can use trans-Arctic routes for at least 30% of the Septembers in the period 2015 – 2029. For late century (the period 2075 - 2089) this percentage increases to 68% and 100% for the low-end and high-end scenarios of climate change, respectively. These percentages illustrate that the average journey time between Europe/North America and Asia currently is still dominated by the Suez and Panama Canal routes, but this will switch gradually towards the trans-Arctic routes. As a result, the average minimum journey time for all European (Arctic + Suez) voyages using open water vessels will decrease from 26 days in 2015 - 2029 to 20 - 23 days by mid-century and 17 - 22 days in 2075 - 2089. The range in number of days refers to the low-end and high-end scenarios of climate change. Reductions in sailing time are less striking for North America because the route via the Panama Canal takes a minimum of only 25 days: this may reduce to 20-– 22 days (12).

The IPCC concluded in 2019 that for stabilised global warming of 1.5°C the annual probability of am Arctic sea ice free September by the end of century is approximately 1%, which rises to 10 - 35% for stabilised global warming of 2°C (36).

Along with a reduction of average journey time, the season for trans-Arctic shipping will become longer. By the end of the century the majority of the Arctic Ocean is expected to be open water for half the year (15). For a high-end scenario of climate change, by late century trans-Arctic shipping may be potentially commonplace, with a season ranging from 4 to 8 months. For the low-end scenario, with global mean temperature stabilization of less than 2°C above preindustrial, the frequency of open water vessel transits still has the potential to double by mid-century with a season ranging from 2 to 4 months (12).

Needless to say that the opportunities for trans-Arctic shipping not only depend on Arctic sea ice changes but on other logistic, economic, and geopolitical factors as well (16). Also, the values presented above are average trends, whilst Arctic sea ice extent varies from year to year. This inter-annual variability will remain a significant factor in route availability throughout the 21st century, motivating increased efforts in seasonal to inter-annual forecasting (17). 

More routes for trans-Arctic shipping will open in the next 50 years

Arctic sea ice is shrinking and thinning rapidly (56) and, as a result, new routes for trans-Arctic shipping emerge. This will reshape shipping corridors between Asia and Europe, in particular. These routes are expected to be navigable during the summer season by mid-century (57) or even earlier (58), and the reduced distance between European and Asian ports will create economic benefits compared to the current Suez Canal route (59). In addition, commercial activities for resource extraction (60) and port facilities and infrastructure will be developed in the Arctic region (61).

A comprehensive evaluation of trans-Arctic shipping under climate change, based on a large number of climate models and four scenarios of climate change, shows that there are a number of Arctic sea routes that will open in the course of this century. The evaluation reveals that trans-Arctic shipping will be relatively risky until about 2045, because of fast ice formation and sea ice ridging in the narrow shallow straits on the routes that will open first for shipping. But other routes across the Arctic, called the Central Arctic Route and the Transpolar Sea Route, without narrow straits, will open in due course as well, lowering the risk of trans-Arctic shipping. Under a high-end scenario of climate change, these routes will probably be open for shipping by the 2070s (55).

For two types of vessels – the most widely used, strengthened Polar Class 7 ships and open water vessels – Arctic navigability was studied for the period from 2023 to 2100. This was done for a moderate climate change scenario (SSP2-4.5). The results show that from 2065 onward these vessels will be able to achieve stable and safe navigation across the Arctic Ocean during the summer and autumn seasons, with the potential for year-round navigation. By 2100, the average annual number of navigable days for strengthened Polar Class 7 ships is 301 days. For open water vessels this number is slightly lower, 247 days (63).

The economic impact of the Arctic sea ice retreat could be significant, reshaping international trade among Asia, Europe, and America. Compared with traditional shipping routes (such as the Suez Canal), sea ice retreat it could reduce maritime transport distance and transport time between Europe and northwestern Asia by 40% and 30%, respectively (64).

Adaptation strategies for cities - General

Solutions to adapt cities for climate change should be an integration of technological, nature-based, and social solutions (47). Examples of technological solutions are air conditioning, building materials that increase the albedo of urban surfaces to reflect sunlight and reduce the heat load of buildings during summer, such as light-coloured paint (48), and permeable pavements that mitigate urban heat and stormwater runoff by reflecting radiation, providing evaporative cooling, and allowing underlying soil to absorb precipitation (49). Examples of nature-based solutions are tree cover to cool transportation corridors (50), and bioswales along streets or constructed wetlands in newly built suburbs help to regulate stormwater runoff (51). Urban social solutions are measures that encourage individuals to change their behaviours and practices (52).

Adaptation strategies - Heat waves in cities

We know a lot about the benefits of adapting to flood risk (32). Adapting cities to heat waves is more complicated, both in design and with respect to quantifying benefits and costs. In Southern Europe, adapting to some of the projected changes could only be achieved by a fundamental, and expensive, re-engineering of each city or water resource system, as significant adaptation to climate extremes has already been implemented and radical changes will be needed to achieve more. In Central Europe, where projected increase of maximum temperature during heat waves is largest (29), there should be capacity and economic resources to support adaptation (33).

Adaptation strategies - Heat stress office buildings

Global warming may have a strong impact on summer cooling costs and heat stress in urban office buildings. This was studied for two types of urban office buildings during the twenty-first century: one with and one without active cooling equipment (19).

No active cooling equipment

In office buildings without active cooling equipment, unfavorable conditions due to overheating have an important influence on the wellbeing and the productivity of the office workers. If these adverse conditions become too severe, precautions are demanded according to international standards and national legislations. ISO standards require additional work breaks if (workplace) climatic conditions deteriorate. This causes lost working hours and economic losses. In a building without active cooling, the number of lost working hours may quadruple between now (reference period 1986-2005) and the far future (2081-2100) under a high-end scenario of climate change (the RCP8.5 scenario). This was shown for a typical Western-European, recently built five-story office building in the Belgian city of Antwerp (19).

Solar blinds and increased (active) ventilation are effective adaptation measures that reduce the amount of lost working hours for this far future period by approximately 60 and 90%, respectively. Moreover, moving employees within the office building has a significant positive effect, reducing the number of lost working hours by 75% in the case of the model set up. Adapted working hours are also effective (19).

Active cooling system

Installing an active cooling system with a fixed threshold temperature nullifies the overheating risk. However, operational costs of such a device will drastically increase over the course of the twenty-first century. For the studied prototype building, cooling demand increases with 25% by 2100. Cooling costs may be reduced significantly, however, by adaptation measures such as external shading or changes in the building ventilation scheme. Adding external solar blinds, for instance, reduces the cooling costs by approximately 30%, according to this study (19).

Adaptation strategies - Flood risk

Flood risk reduction via land-use planning

Zoning policies can be used to limit the exposure to flooding of people and assets. Zoning regulations entail the determination of areas with a certain flood risk (i.e. the 100-year flood zone) and setting up certain land-use requirements for these zones. Such requirements could constitute, for instance, a complete ban, restricting certain uses, requiring certain building standards, giving recommendations and providing information to inhabitants in certain zones (7). In many countries (e.g. Germany, The Netherlands, UK), municipalities play an important role in flood risk management as they can specify measures for the minimisation of the damage potential for flood-prone areas in land-use plans (8). Their land- use plans tell which land use is allowed on each plot, and flood issues could, theoretically, be incorporated, but this is not always the case in practice. 

Spatial planning can also play a role in limiting fatalities by optimising the possibility to reach safe places in case of flooding, be it within the flooded region (vertical evacuation, for instance to higher floors or designated flood shelters) or out of the affected region (horizontal evacuation). In addition, spatial planning can facilitate the evacuation of people away from threatened areas by making sure the main road network is elevated and thus able to be used longer in case of flooding (9). Old levees or local embankments can potentially be used for this and may have an extra compartmentalisation effect (10). Such compartmentalisation could limit the flood extent and thus fatalities and damage as well (10). 

Flood risk reduction via​ private damage-reducing measures

Two types of building precautionary measures aim at minimising damage (11):

• wet flood proofing: flood-adapted use and equipment of buildings. Examples of wet flood proofing are the following: to adapt the building use, which means that cellars and endangered floors are not used cost intensively; to adapt the interior fitting which means that in endangered floors only waterproofed building material and movable small interior decoration and furniture are used; or to safeguard possible sources of contamination, such as an oil tank of a heating system.
• dry flood proofing: sealing, reinforcement and shielding. Examples of dry flood proofing measures are: adapting the building structure via an elevated configuration; to waterproof seal the cellar, e.g. by constructing the basis and walls of buildings out of concrete that is non-permeable; or to deploy mobile flood barriers such as temporary flood guards. 

Adaptation strategies - Transport infrastructure

Successful adaptation strategies to a large extent consist of awareness building and incentives to think and act with a long-term perspective. Important ingredients are advanced information and control systems, contingency planning, staff training, and proper maintenance strategies. Additionally, improved vehicle technology and communication systems capable of transmitting and processing advanced information on natural hazards and other risks should support policy action. Expensive investments in transport infrastructures can be limited: with adapted maintenance routines, most infrastructure measures should be possible within standard renewal cycles of the assets and thus will cause zero or only moderate additional costs (2).

High-income countries with good infrastructures and low population densities (northern Europe) will be less exposed to extreme weather risks than countries with low income level and poor quality infrastructure but yet relatively high densities of transport and population (3). It is expected, however, that better technologies and higher safety standards will influence the accident rate more than the expected weather changes (2).

Road and rail transport

There seems to be a larger adaptation potential in road transport than in rail: technology can improve the coordination of institutions and provide users with the relevant information in real time, and car-to-car and car-to-infrastructure communication technologies are expected to enter the market in the coming decades and will be connected to weather information systems (6).

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 (6).

The additional annual cost for the upgrade of asphalt binder for the European Union is € 38.5 - 135 million between 2040 and 2070 and € 65 - 210 million between 2070 and 2100, according to model projections for a moderate scenario of climate change (SRES A1B). Nevertheless, it should be noted that road surfaces are typically replaced every 20 years; therefore, climatic impacts could be considered at the time of replacement (37).

Future costs for bridge protection against flooding have been estimated at over € 500 million per year for the European Union (38). Adaptive construction and maintenance practices can include the construction of adequate drainage and the use of permeable pavements and polymer modified binders (39).

Inland navigation

In the class of ship and operation-related measures, the most promising measures to adapt to more frequent low-flow conditions in the future involve weight-reducing technologies, flat hulls (for push boat technology), and the use of coupling convoys (especially in the Rhine river). In terms of infrastructure measures, large infrastructural works are not justified with respect to climate change, due to the large investment costs and the limited benefit of such projects until 2050. However, even under current conditions, there exists a strong need for improved maintenance of the waterways. The possible impact of climate change until 2050 on the Rhine hydrology will not likely be strong enough to induce any significant shift in modal shares (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 Europe.

1. Brown et al. (2014)
2. Michaelides et al. (2014)
3. Molarius et al. (2012), in: Michaelides et al. (2014)
4. Doll et al. (2014a)
5. Przyluski et al. (2011), in: Doll et al. (2014)
6. Doll et al. (2014b)
7. Merz et al. (2007), in: Kreibich et al. (2015)
8. Böhm et al. (2004), in: Kreibich et al. (2015)
9. Kreibich et al. (2015)
10. Klijn et al. (2010); Koks et al. (2014), both in: Kreibich et al. (2015)
11. ICPR (2002), in: Kreibich et al. (2015)
12. Melia et al. (2016)
13. Lasserre (2014), in: Melia et al. (2016)
14. Browse et al. (2013), in: Melia et al. (2016)
15. Barnhart et al. (2015); Laliberté et al. (2016), both in: Melia et al. (2016)
16. Arctic Marine Shipping Assessment (2009); Hansen et al. (2016), both in: Melia et al. (2016)
17. Eicken (2013); Guemas et al. (2014); Hawkins et al. (2015); Stroeve et al. (2014b), all in: Melia et al. (2016)
18. Nissen and Ulbrich (2017)
19. Hooyberghs et al. (2017)
20. Przyluski et al. (2011), in: European Environment Agency (2017)
21. Nemry and Demirel (2012); Ciscar et al. (2014), both in: European Environment Agency (2017)
22. Ciscar et al. (2014), in: European Environment Agency (2017)
23. Storer et al. (2017)
24. De Villiers and Van Heerden (2001), in: Storer et al. (2017)
25. Kim and Chun (2011), in: Storer et al. (2017)
26. Sharman et al. (2006), in: Storer et al. (2017)
27. Forzieri et al. (2018)
28. Forzieri et al. (2014), in: Forzieri et al. (2018)
29. Guerreiro et al. (2018)
30. UN-HABITAT (2011), in: Guerreiro et al. (2018)
31. Guerreiro et al. (2017a); Guerreiro et al. (2017b), both in: Guerreiro et al. (2018)
32. Ward et al. (2017), in: Guerreiro et al. (2018)
33. Tapia et al. (2017), in: Guerreiro et al. (2018)
34. Matulla et al. (2018)
35. Bubeck et al. (2019)
36. IPCC (2019a)
37. EC (2012), in: UNECE (2020)
38. EC (2012); ECE (2015), both in: UNECE (2020)
39. Willway et al. (2008), in: UNECE (2020)
40. UNECE (2020)
41. Hambly et al. (2012); Palko (2017), both in: UNECE (2020)
42. ECE (2013), in: UNECE (2020)
43. PIANC (2008), in: UNECE (2020)
44. Jonkeren et al. (2007), in: UNECE (2020)
45. Christodoulou and Demirel (2018), in: UNECE (2020)
46. EUCC-D (2013), in: UNECE (2020)
47. Lin et al. (2021)
48. Francis and Jensen (2017), in: Lin et al. (2021)
49. Li et al. (2013), in: Lin et al. (2021)
50. Hobbie and Grimm (2020), in: Lin et al. (2021)
51. Pauleit et al. (2019), in: Lin et al. (2021)
52. Sheppard (2011), in: Lin et al. (2021)
53. Hosseinzadehtalaei et al. (2020)
54. Kharin et al. (2018); Cannon and Innocenti (2019), both in: Hosseinzadehtalaei et al. (2020)
55. Li and Lynch (2023)
56. Kacimi and Kwok (2022), in: Li and Lynch (2023)
57. Smith and Stephenson (2013), in: Li and Lynch (2023)
58. Mudryk et al. (2021), in: Li and Lynch (2023)
59. Lynch et al. (2022), in: Li and Lynch (2023)
60. Bugnot et al. (2021), in: Li and Lynch (2023)
61. Hanson and Nicholls (2020), in: Li and Lynch (2023)
62. Wang et al. (2024)
63. Zhao et al. (2024)
64. Liu and Kronbak (2010); Schøyen and Bråthen (2011), both in: Zhao et al. (2024)
65. Prosser et al. (2023)