4 The Consequences of Climate Change and Extreme Weather Events This chapter looks at vulnerability analyses for a large number of sectors and areas. Generally, each section is structured as follows: • Description of the system and background information. • Current vulnerabilities and past major events. • Consequences and costs of climate change and extreme weather events. • Adaptive measures and considerations. • Research and development needs. • Recommendations. Section 4.8 summarises the consequences and measures in econo- mic terms. 4.1 Communications 4.1.1 Roads The consequences of climate change on the road network are consider- able. Increasing precipitation and increased flows lead to flooding, the washing away of roads, damaged bridges and an increased risk of land collapse, landslide and erosion. With increased temperatures damage moves from being frost-related to heat and water-related, though concrete bridge maintenance costs are reduced. 161 The Consequences of Climate Change and Extreme Weather Events SOU 2007:60 Division of responsibility The overall objective of transport policies is to secure an econo- mically efficient and highly sustainable transport system for citiz- ens and businesses throughout the country, which places great demands on accessibility, passability and safety. The Swedish Road Administration is the agency responsible for this sector. The road maintainer is legally responsible for the roads, and this includes ensuring that the roads are passable for third-party/passing traffic. State subsidies are given to private road maintainers for the maintenance of approximately a quarter of the private roads. In the event of major damage, those responsible for private roads can apply to the Swedish Road Administration for financial compen- sation, such as for wear. The road network today Sweden’s roads can be broken down according to responsibility, significance or importance to the country as a whole. Breaking down the road network according to responsibility gives 98,000 km of state roads, 37,000 km of local authority roads and 280,000 km of private roads, 150,000 km of which are forest roads. The state road network is split into European, national and county roads. Moreover, the Swedish government has defined a backbone road network of national interest in accordance with the Swedish Environmental Code, largely comprised of European and national roads. The Swedish European roads are part of the trans-European transport network. The road network is divided into five components when consi- dering climate impact: • Roads (surfacing, pavement, subgrade and culverts). • Bridges. • Tunnels. • Ferry berths. • Operation and maintenance. Lifetimes vary greatly, from the technical lifetime of road surfacing of about 20 years to the more than 100 years of bridges and tunnels. The vulnerability analysis is based on the existing road system and a geographic distribution that largely corresponds to 162 SOU 2007:60 The Consequences of Climate Change and Extreme Weather Events the Swedish Road Administration’s organisation and the natural boundaries that can be construed from climate change, primarily the dividing line between the southeast and southwest parts of the country and dividing line between the southern part and Mälardalen. Figure 4.1 Geographic division of the country applied in the vulnerability analyses and the Swedish National Road Administration’s regional divisions Source: Swedish National Road Administration's Report to the Transport Group of the Climate and Vulnerability Committee. Large parts of the sparse state road network lack viable diversion routes. Densely populated areas lacking larger topographic barriers generally offer good alternatives for traffic diversion in the event of problems. In rural areas traffic can be diverted from newer stretches of road to older ones, if they remain. In the event of long-term disruptions temporary roads and bridges can be built to minimise losses to society. The analysis presented in the Swedish Road Administration's Report to the Commission on Climate and Vulnerability, appendix B 1, includes the state network. It does not, however, include local authority and private roads and streets. Forest roads have been studied in brief in the analysis for the forestry sector (section 163 The Consequences of Climate Change and Extreme Weather Events SOU 2007:60 4.4.1). The vulnerability analysis is based primarily on the global ECHAM4 model, emission scenario A2 and the 2071-2100 time span. Other scenarios are taken into account if there are considerable differences. The focus is on road network components judged to be most affected by climate change. Sensitive climate factors and past extreme events The primary climate factors affecting the road network are precipitation, high flows, icing, temperature, sea level and wind. Precipitation affects road systems mainly through the build up of ground water and runoff into watercourses immediately after rain or due to snow melt. Persistent rain raises the ground water level and increases pore pressure in the soil, which impairs natural slope stability. High flows in large and medium-size watercourses give rise to an erosion risk that affects watercourse embankments and an accompanying risk of landslide, as well as impact on bridge trestle work and superstructures. High flows are seen in southern Sweden mostly in late autumn, early winter and early spring, while in northern Sweden they are mostly seen during snow melt. Heavy rain leads to high flows in small watercourses, primarily in summer and autumn, with the risk of erosion, flooding, the washing away of roads and impact on, for instance, culverts. Heavy rain also entails a risk of flooding, for example, in and around underpasses. Snow or supercooled rain on the road affects passability and traffic safety. Ground frost and moderate and high temperatures are of significance to road load bearing capacity and durability. Temperature fluctuations also affect bridge constructions, as do wind and ice. Sea levels affect ferry services and low-lying tunnels. Heavy precipitation was recorded for most years between 1994 and 2001. During this period there were some 200 events involving major damage caused by high flows. The damages break down as follows: flooding 25 percent, roads washed away 50 percent, landslides 20 percent and undermined bridge trestle work 5 percent. The greatest number of incidents was reported in western Götaland and Värmland up to central Norrland. The cause of the damages was a combination of extreme weather events and geological and topographical conditions. A few major incidents have occurred since 2001. Several high road embankments were washed away in Hagfors in 2004 after 164 SOU 2007:60 The Consequences of Climate Change and Extreme Weather Events heavy rain. The total costs exceeded SEK 20 million. In the summer of 2006 a road embankment near Ånn was washed away after heavy rain and an accompanying high flow. The road was repaired after two weeks at a cost of SEK 6 million. In December 2006 there was a large landslide south of Munkedal. The landslide encompassed an area measuring 550 metres by 250 metres in a depression through which the E6 trans-European road runs. The repairs took almost two months. The direct costs for repairing the road network, including the restoration of bypass roads and ferry services provided during the disruption, totalled some SEK 120 million, excluding the cost of restoring the Taske river. Costs for diversions and other incidentals comprised more than 50 percent of the direct costs. The indirect consequences were extensive. The two allocated diversion routes for long-distance traffic entailed extra journeys of 40 and 55 km respectively. The indirect costs have been estimated at the same magnitude as the direct costs. The costs of all major incidents due to high flows and landslides the past 12 years are estimated at SEK 1,200 million. Work is underway at the Swedish Road Administration to produce new specification requirements for construction and improvement work. These will include risk-based performance specifications regarding high flows and take into account the consequences of damage. A risk survey and a risk analysis of the existing road network have been initiated. The emphasis is on erosion and landslide risks, as well as stretches of road vulnerable to closure. Methods to find road culverts exhibiting high risk levels during heavy rain are under development. The methods used to determine the water flow and water levels to be considered in the design process are being revised. A review of the rules for erosion protection is also planned. Consequences of climate change and extreme weather events together with damage costs – precipitation, flows and sea level In the scenarios, winter, spring and autumn precipitation generally increases throughout the country. Snow pack duration and total water content decrease throughout the country. Snowfall declines in the southern parts of the country, while a slight short-term increase, which will eventually show a gradual decline, is seen in the northern parts. In all, this increases effective precipitation (precipi- 165 The Consequences of Climate Change and Extreme Weather Events SOU 2007:60 tation minus evaporation), synonymous with runoff. A lower incidence of ground frost due to higher temperatures will lead to increased ground water formation during winter, affecting suscep- tibility to landslide. Figure 4.2 shows the change in effective precipitation during