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Potential Impacts of Climate Change on U.S. Transportation 5 Meeting the Challenges Adaptation to climate change would be necessary even if drastic mitigation measures were taken immediately to stabilize or even eliminate greenhouse gas (GHG) emissions (IPCC 2007). The effects of such global climate changes as warming temperatures and sea level rise occurring today reflect emissions of GHGs released into the atmosphere over the past century. Because of these long-lasting effects, the actions taken by transportation professionals today have implications for how the transportation system will respond to climate change in the near and long terms. The first section of this chapter is organized on the basis of timescales that transportation decision makers must consider in determining how best to adapt to climate change. In the short term (i.e., the next several decades), transportation professionals are likely to have operational responses to changing climate conditions and climate extremes. Operators of transportation systems already react to many climate changes, particularly extreme events (e.g., intense precipitation, intense tropical storms) and can rapidly adapt operating and maintenance practices for those climate conditions projected to increase in frequency or intensity. Rehabilitating or retrofitting infrastructure requires a longer time horizon because engineers design many infrastructure facilities with long service lives in mind (see Chapter 4), thereby providing fewer opportunities for adapting to changing climate conditions without incurring significant costs. Adapting facilities for climate change may also involve the reevaluation and development of design standards—a process that typically entails a lengthy research and testing program. Finally, constructing new transportation infrastructure or providing major additions to existing transportation systems requires the longest time horizon. Transportation systems shape land use and development
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Potential Impacts of Climate Change on U.S. Transportation patterns, and in turn, population growth and economic development stimulate demand for new infrastructure facilities to support growth. In both cases, decisions made today about where to locate or expand transportation infrastructure establish development patterns that persist for generations and are difficult to change. These decisions should be weighed carefully to ensure that people and businesses are not placed in harm’s way as projected climate changes unfold. Following discussion of these topics, the chapter turns to many cross-cutting issues—flood insurance; monitoring technologies and new materials; data, models, and decision support tools; and new partnerships and organizational arrangements—that can help facilitate adaptation to climate change or bring climate change issues into the decision-making process. The chapter ends with the committee’s findings. ADAPTATION STRATEGIES Annexes 5-1A through 5-1C summarize a wide range of adaptation measures that can be used to address many of the climate change impacts discussed in Chapter 3 (see Annex 3-1). Potential adaptations are identified for land, marine, and air transportation, respectively, by response category: (a) changes in operations, (b) changes in infrastructure design and materials, and (c) other. No attempt is made to estimate the relative costs or effectiveness of these measures, although such analyses would be necessary to evaluate specific infrastructure investment alternatives. The remainder of this section addresses the key issues and opportunities for adaptation in each response category. Operational Responses The most rapid response to the impacts of climate change is likely to come through changes in transportation operating and maintenance practices.1 Every U.S. transportation provider already experiences the adverse impacts of weather on operations under a diverse range of climate conditions. For example, approximately 75 percent of air travel delays in the National Airspace System are weather related (L. Maurice and M. Gupta, presentation to the committee, Jan. 4, 2007). Slick pavement and adverse weather 1 This section draws heavily on the paper by Lockwood (2006) commissioned for this study.
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Potential Impacts of Climate Change on U.S. Transportation contribute to nearly one-quarter of all highway crashes and about 7,400 fatalities annually.2 In addition, snow, ice, rain, and fog cause about 15 percent of total delays on the nation’s highways (FHWA 2004; NRC 2004b). Weather also causes delays and interruptions in service for railroad and marine transportation.3 Transportation agencies expend considerable resources to address these conditions. For example, snow and ice control accounts for about 40 percent of annual highway operating budgets in snowbelt states (FHWA 2006a). Hurricane response is a major focus of transportation operations in states bordering the Gulf Coast. Collaboration between departments of transportation (DOTs) and emergency response personnel has improved, particularly in those areas of the country subject to recurring natural disasters—the Gulf Coast (hurricanes) and California (earthquakes and wildfires)—but still has a long way to go. Climate change is altering the frequency, intensity, and incidence of weather events. Changes in Frequency of Extreme Weather Events With changes in the frequency of extreme weather events, operational responses treated today on an ad hoc, emergency basis are likely to become part of mainstream operations. One could imagine, for example, that if strong (Category 4 and 5) hurricanes increased in frequency as is likely, widespread establishment of evacuation routes and use of contraflow operations4 in affected areas might become as commonplace as snow emergency routes in the Northeast and Midwest. Mainstreaming such responses will require expanding the scope of the traditional operating focus of DOTs on traffic and incident management to include weather management, as well as improved training for operating personnel. Increases in Intensity of Weather Events Climate change is expected to trigger more extreme weather events, such as more intense precipitation, which are likely to produce areawide emergen- 2 Based on averages from 1995–2004 data collected by the National Highway Traffic Safety Administration and analyzed by Mitretek Systems. 3 See, for example, Changnon (2006) on the impacts of weather and climate on American railroading and a report by the Office of the Federal Coordinator for Meteorological Services and Supporting Research on the impacts of weather on surface transportation modes (OFCM 2002). 4 Contraflow involves the reversal of traffic flow on one or more of the inbound lanes and shoulders of roads and highways for use in the outbound direction to increase evacuation capacity in an emergency by using both sides of a roadway.
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Potential Impacts of Climate Change on U.S. Transportation cies and may require evacuation of areas vulnerable to flooding and storm surge. In the wake of September 11, 2001, and Hurricanes Katrina and Rita, the U.S. Department of Homeland Security has mandated an all-hazards approach to emergency planning and response and encouraged better evacuation planning (DHS 2006). Coordination among state and local emergency managers—the first responders in an emergency—has improved, and emergency operations centers (EOCs) have been established in many metropolitan areas as command posts that can be activated rapidly in an emergency. Typically, transportation is a support function, but the critical role it plays in emergency response and especially in evacuation—a role that is likely to become more important as the climate changes—should be strengthened through increased collaboration between emergency managers and transportation providers and more representation of transportation agencies and private transportation providers at EOCs. Operators of transportation systems also need to work more closely with weather forecasters and emergency response planners to convey their own lead-time requirements for providing the necessary personnel and equipment in an evacuation and protecting their own assets. Finally, a greater emphasis on emergency management as a separate functional responsibility within DOTs and other transportation providers is needed. Regional transportation management centers (TMCs) provide one location through which collaboration between transportation providers and emergency managers can occur (see Box 5-1). TMCs are currently focused on traffic monitoring and incident management through rapid deployment of police, fire and rescue, and emergency medical services. In some metropolitan areas, new functions are being added, such as better weather information and greater use of real-time traffic advisories, as well as links with emergency managers. Some TMCs are also serving as EOCs. However, integration of weather and emergency management functions in TMCs is still in its infancy according to a recent U.S. Department of Transportation assessment (FHWA 2006b). Changes in Incidence of Weather Patterns Climate changes will bring new weather patterns to previously unaffected areas of the United States. These changes, however, may not necessarily require the development of new operating and maintenance strategies. The United States has a diverse climate, ranging from subtropical to arctic
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Potential Impacts of Climate Change on U.S. Transportation BOX 5-1 Transportation Management Centers Improving the efficiency of the existing highway network involves the application of technologies, such as intelligent transportation systems (ITS), and control strategies, such as ramp metering, dynamic message signs, and incident management. In many large metropolitan areas, these developments have been accompanied by establishment of regional transportation management centers (TMCs), which are seen as the cockpit or nerve center for monitoring traffic incidents and providing rapid police response, crash clearance, and travel advisories. Many TMCs are manned by staff from multiple agencies and jurisdictions working as a team. Some TMCs are focused primarily on traffic and incident management. Others, such as Houston TranStar, have a broader scope. Opened in 1996, Houston TranStar is a consortium partnership of transportation and emergency management agencies in the greater Houston area housing engineers, law enforcement personnel, information technology specialists, and emergency managers. In addition to traffic monitoring and incident control, emergency management personnel from the Harris County Office of Emergency Management monitor potential emergencies due to severe weather using state-of-the-art technology, such as flood warning monitors, Doppler radar, satellite imagery, and weather data from the National Weather Service, to provide the public with real-time information. The city of Chicago recently opened a new City Incident Center (CIC), which integrates the city’s homeland security efforts with traffic services, among other activities. CIC follows on the creation of a Traffic Management Authority in 2005, dedicated to improving traffic flow through ITS technology and centralized control systems. The new facility will have positions dedicated to traffic management but will also provide a central location for communication among dispatch operators from all the relevant city departments so they can respond rapidly and effectively in the event of an emergency (Inside ITS 2006). and from arid to wet, with several regions being subject to temperature extremes and such events as blizzards, hurricanes, tornadoes, floods, wildfires, avalanches, and mudslides. As climate patterns change, the transfer of best practices from one location to another will be essential. A mechanism is needed to encourage such information exchange, involving all
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Potential Impacts of Climate Change on U.S. Transportation transportation modes. This effort should build on existing technology transfer mechanisms, such as the Technology Implementation Group of the American Association of State Highway and Transportation Officials (AASHTO).5 Design Strategies Operational responses are geared to addressing near-term impacts of climate change. To make decisions today about rehabilitating or retrofitting transportation facilities, especially those with long design lives (see Table 4-2 in the previous chapter), transportation planners and engineers must consider how climate changes will affect these facilities 50 years or more from now. Adapting to climate change will also require reevaluation, development, and regular updating of design standards that guide infrastructure design. The purpose of design standards is to provide engineers with guidance on how to construct infrastructure for safe and reliable performance.6 These standards represent the uniform application of the best engineering knowledge, developed through years of experimental study and actual experience. Often they become embedded in regulatory requirements and funding programs.7 Design standards embody trade-offs between performance (e.g., safety, reliability) and cost. Faced with a myriad of factors that can affect performance, engineers typically select the most demanding parameter—the 100-year storm, the heaviest truck, the most powerful wind speed—as the basis for design, thereby building in a safety margin to minimize the chances of failure. Environmental factors are integral to the design of transportation infrastructure. Conditions such as temperature, freeze–thaw cycles, and duration and intensity of precipitation determine subsurface and founda- 5 The primary objective of AASHTO’s Technology Implementation Group, which grew out of an AASHTO task force’s successful effort to implement products of the Strategic Highway Research Program, is to provide leadership to state DOTs, local governments, and industry in the selection and promotion of ready-to-implement technologies. 6 This section draws heavily on the paper by Meyer (2006) commissioned for this study. 7 To be eligible for federal funding, for example, state and local governments must comply with federal standards with respect to lane and shoulder widths on highways and bridge clearances over navigable waterways. If the infrastructure is damaged or destroyed, federal agencies and insurers typically allow renovation or rebuilding only to replacement standards; upgrading is not a reimbursable cost.
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Potential Impacts of Climate Change on U.S. Transportation tion designs, choices of materials, and drainage capacity. The issue is whether current design standards are adequate to accommodate the climate changes projected by scientists. Table 5-1 provides an assessment by Meyer (2006) of the principal climate-induced changes and their implications for infrastructure design in both the short and long terms. Looking across all climate changes, the author notes that the most dominant impact is on those design elements most associated with forces resulting from water flows. This finding is not surprising in view of the extensive damage to transportation infrastructure and buildings caused by flooding and storm surge in Hurricanes Katrina and Rita. Climate changes, however, will not affect the design of all infrastructure modes equally, a second important observation. For example, wave action is more critical than temperature changes for coastal bridge design. Finally, climate extremes, such as stronger wind speeds, increased storm surges, and greater wave heights, will place the greatest demands on infrastructure because they are likely to push the limits of the performance range for which facilities were designed. How should engineering design decisions be modified to address climate change, particularly for longer-lived infrastructure for which the uncertainties are greater regarding the magnitude and timing of climate changes? One option is to build to a more robust standard, assuming a greater frequency and magnitude of extreme events, without a full understanding of future risks and presumably at greater cost. This strategy could be appropriate for major facilities in vulnerable locations (e.g., critical bridges and evacuation routes), but its high costs necessitate a highly selective approach. Another option is to upgrade parallel routes, but this alternative depends on the availability of right-of-way and the cost of upgrading. A third option is to build infrastructure with shorter design lives, presumably at lower cost, to be retrofitted as more knowledge about future climate conditions is gained. This alternative probably is not viable in the United States because of the disruption and negative public reaction resulting from more frequent retrofits of major facilities. Most states are adopting a “fast in, fast out, and stay out” approach to major reconstruction projects. A final option is to hedge by building to current standards or making marginal improvements, recognizing that the infrastructure remains at risk and may require major improvements in the future. This alternative poses many of the same problems as the previous one. All four options involve important cost–risk reduction trade-offs that engineers
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Potential Impacts of Climate Change on U.S. Transportation TABLE 5-1 Climate-Induced Changes That Could Influence Transportation Infrastructure Design Climate-Change Phenomenon Changes in Environmental Condition Design Implications Temperature change Rising maximum temperature; lower minimum temperature; wider temperature range; possible significant impact on permafrost Over the short term,a minimal impact on pavement or structural design; potential significant impact on road, bridge scour, and culvert design in cold regions Over the long term, possible significant impact on pavement and structural design; need for new materials and better maintenance strategies Changing precipitation levels Worst-case scenario, more precipitation; higher water tables; greater levels of flooding; higher moisture content in soils Over the short term, could affect pavement and drainage design; need for greater attention to foundation conditions, more probabilistic approaches to design floods, more targeted maintenance Over the long term, definite impact on foundation design and design of drainage systems and culverts; impact on design of pavement subgrade and materials Wind loads Stronger wind speeds and thus loads on bridge structures; more turbulence Over the short term, design factors for design wind speed might change; wind tunnel testing will have to consider more turbulent wind conditions Over the long term, need for materials of greater strength; impact on design considerations for suspended and cable-stayed bridges Sea level rise Rising water levels in coastal areas and rivers; increases in severe coastal flooding Over the long term, greater inundation of coastal areas; need for more stringent design standards for flooding and building in saturated soils; greater protection of infrastructure needed when higher sea levels combine with storm surges Greater storm surges and wave heights Larger and more frequent storm surges; more powerful wave action Over the short term, need for design changes to bridge height in vulnerable areas; need for more probabilistic approach to predicting storm surges Over the long term, need for changes to bridge design, both superstructure and foundations; changes in materials specifications; and more protective strategies for critical components aFor purposes of this table, short term is defined as the next 30 to 40 years; long term is from 40 to 100 years. Source: Meyer 2006, Table 1.
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Potential Impacts of Climate Change on U.S. Transportation and planners can best address through a more strategic, risk-based approach to design and investment decisions, such as that described in the previous chapter. The approach taken by Transit New Zealand to determine the necessity and feasibility of taking action now to protect the state highway network from the potential future impacts of climate change could also be instructive (see Box 5-2). More fundamentally, the scientific community and professional associations must reevaluate design standards for transportation infrastructure that take climate change into account and begin the lengthy process of developing new standards where appropriate. Reexamination of design standards can be prompted by a single event, such as the damage to coastal highway bridges from Hurricane Katrina, when it became evident that the current state of practice—designing bridges for a riverine environment and a 50-year storm—was inadequate. The Federal Highway Administration (FHWA) not only approved and shared in the cost of rebuilding the damaged bridges to a higher design standard but also recommended the development of more appropriate bridge design standards in general for a coastal environment that would take into account the combined effects of storm surge and wave action and assume a more severe storm event (e.g., a 100-year or even 500-year storm) (FHWA 2005a).8 Typically, however, the development of design standards follows a time-consuming and systematic process that involves professional organizations in an extensive research and testing program over a period of decades. Once the standards are in place, engineers are understandably reluctant to change them. A combination of the length of time required to modify or develop new standards, the institutional procedures for approval of standards (vetting any changes through professional committees of practicing engineers), and the use of well-established standards as evidence of “good practice” in litigation leads to a conservative approach to change. Developing standards to address climate change in a timely manner thus will require leadership by the scientific community and professional associations and, given the scope of potential impacts, a broad-based, federally sponsored research program that must begin soon. A good model is the congressionally mandated National Earthquake 8 AASHTO and state DOTs are leading this initiative, and research on wave forces and wave load design practices is now being undertaken by universities and the U.S. Department of Transportation’s Turner–Fairbank Highway Research Center, among others.
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Potential Impacts of Climate Change on U.S. Transportation BOX 5-2 Climate Change and Asset Management: New Zealand Transit’s Approach to Addressing Impacts of Climate Change Under the 2004 Resource Management (Energy and Climate Change) Amendment Act—New Zealand’s principal legislation for environmental management—Transit New Zealand was required to take into account the effects of climate change as it plans, constructs, and maintains the state highway network (Kinsella and McGuire 2005). The key climate changes of concern to state highways are sea level rise, coastal storm surges, and increased frequency and intensity of heavy rainfall events. The primary assets at risk are bridges, culverts, causeways and coastal roads, pavement surfaces, surface drainage, and hillside slopes. Transit New Zealand proceeded with a two-stage assessment to identify those areas requiring action. Stage 1 involved assessing the need to act now to manage future potential impacts of climate change. Three criteria were used: Level of certainty that the climate change impact will occur at the magnitude predicted in the specified time frame, Intended design life of the state highway asset, and Capacity of the agency’s current asset management practice to manage the impact. The results of the Stage 1 assessment revealed that current asset management practice is generally adequate to deal with impacts of climate change for most of the network, but that bridges and culverts with an intended design life of more than 25 years may require case-by-case consideration to ensure protection (Kinsella and McGuire 2005). Stage 2 involved assessing the economic feasibility of acting now to manage future potential impacts of climate change and was focused on bridges and culverts with design lives of greater than 25 years. Making several simplifying assumptions, the analysis examined three options: (a) doing nothing, (b) retrofitting all existing bridges and culverts now to avoid future climate change impacts, and (c) designing all new bridges and culverts to accommodate future climate changes to 2080. The analysis revealed that it would not be economical to retrofit the existing stock of bridges and culverts, but it
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Potential Impacts of Climate Change on U.S. Transportation would be preferable to repair the assets when a specific loss or need became evident. The primary reasons for this conclusion were uncertainties about where and when the impacts of climate change will manifest themselves and the historical number of bridges and culverts lost prematurely because of other events. Retrofitting all new bridges and culverts to take climate change into account was also determined not to be economical. Nevertheless, the agency decided that, where possible, provision should be made for subsequent retrofitting (either lifting or lengthening the bridge) in the event impacts are experienced. For major bridges (and culverts) where retrofitting is not practical, the structure should be designed for projected future impacts of climate change on the basis of the best available information (Kinsella and McGuire 2005). Transit New Zealand has amended its Bridge Manual to include consideration of relevant impacts of climate change as a design factor. In addition, the agency will continue to monitor climate change data and developments and review its policy when appropriate. Hazard Reduction Program, begun in 1977, which has provided much of the underlying research for seismic standards (see Box 5-3). New Infrastructure Investment, Transportation Planning, and Controls on Land Use One of the most effective strategies for reducing the risks of climate change is to avoid placing people and infrastructure in vulnerable locations, such as coastal areas. Chapter 3 described the continuing development pressures on coastal counties despite the increased risk of flooding and damage from storm surge and wave action accompanying projected rising sea levels. Many areas along the Atlantic, Gulf, and Pacific coasts will be affected. Once in place, settlement patterns and supporting infrastructure are difficult to change. In New York City, for example, a major concern of emergency planners is handling the evacuation of some 2.3 million New Yorkers from flood-prone areas in the event of a Category 3 or greater hurricane (New York City Transit 2007). Continued development of such vulnerable areas
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Potential Impacts of Climate Change on U.S. Transportation Potential Climate Change Impacts on Land Transportation (Highways, Rail, Pipeline) Adaptation Options Operations and Interruptions Infrastructure Changes in Operations Changes in Infrastructure Design and Materials Other Return of some coastal areas to nature Precipitation: increase in intense precipitation events Increases in weather-related delays Increases in traffic disruptions Increased flooding of evacuation routes Disruption of construction activities Changes in rain, snowfall, and seasonal flooding that affect safety and maintenance operations Increases in flooding of roadways, rail lines, and subterranean tunnels Overloading of drainage systems, causing backups and street flooding Increases in road scouring, road washout, damages to railbed support structures, and landslides and mudslides that damage roadways and tracks Impacts on soil moisture levels, affecting structural integrity of roads, bridges, and tunnels Expansion of systems for monitoring scour of bridge piers and abutments Increase in monitoring of land slopes and drainage systems Increases in monitoring of pipelines for exposure, shifting, and scour in shallow waters Increases in real-time monitoring of flood levels Integration of emergency evacuation procedures into operations Protection of critical evacuation routes Upgrading of road drainage systems Protection of bridge piers and abutments with riprap Increases in culvert capacity Increases in pumping capacity for tunnels Addition of slope retention structures and retaining facilities for landslides Increases in the standard for drainage capacity for new Greater use of sensors for monitoring water flows Restriction of development in floodplains
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Potential Impacts of Climate Change on U.S. Transportation Adverse impacts of standing water on road bases Increases in scouring of pipeline roadbeds and damages to pipelines transportation infrastructure and major rehabilitation projects (e.g., assuming a 500-year rather than a 100-year storm) Precipitation: increases in drought conditions for some regions Increased susceptibility to wildfires, causing road closures due to fire threat or reduced visibility Increased susceptibility to wildfires that threaten transportation infrastructure directly Increased susceptibility to mudslides in areas deforested by wildfires Vegetation management Precipitation: changes in seasonal precipitation and river flow patterns Benefits for safety and reduced interruptions if frozen precipitation shifts to rainfall, depending on terrain Increased risk of floods from runoff, landslides, slope failures, and damage to roads if precipitation changes from snow to rain in winter and spring thaws Storms: more frequent strong hurricanes (Category 4–5) More debris on roads and rail lines, interrupting travel and shipping More frequent and potentially more extensive emergency evacuations Greater probability of infrastructure failures Increased threat to stability of bridge decks Increased damage to signs, lighting fixtures and supports Emergency evacuation procedures that become more routine Improvements in ability to forecast landfall and trajectory of hurricanes Changes in bridge design to tie decks more securely to substructure and strengthen foundations Strengthening and heightening of levees Restriction of further development in vulnerable coastal locations
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Potential Impacts of Climate Change on U.S. Transportation Potential Climate Change Impacts on Land Transportation (Highways, Rail, Pipeline) Adaptation Options Operations and Interruptions Infrastructure Changes in Operations Changes in Infrastructure Design and Materials Other Decreased expected lifetime of highways exposed to storm surge Improvements in monitoring of road conditions and issuance of real-time messages to motorists Improvements in modeling of emergency evacuation Increases in drainage capacity for new transportation infrastructure or major rehabilitation projects (e.g., assuming more frequent return periods) Removal of traffic bottlenecks on critical evacuation routes and building of more system redundancy Adoption of modular construction techniques where infrastructure is in danger of failure Development of modular traffic features and road sign systems for easier replacement Increase in flood insurance rates to help restrict development Return of some coastal areas to nature
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Potential Impacts of Climate Change on U.S. Transportation ANNEX 5-1B Potential Climate Changes, Impacts on Marine Transportation and Adaptation Options Potential Climate Change Impacts on Marine Transportation Adaptation Options Operations and Interruptions Infrastructure Changes in Operations Changes in Infrastructure Design and Materials Other Temperature: increases in very hot days and heat waves Impacts on shipping due to warmer water in rivers and lakes Temperature: decreases in very cold days Less ice accumulation on vessels, decks, riggings, and docks; less ice fog; fewer ice jams in ports Improvement in operating conditions from less ice accumulation, fog, and jams Temperature: increases in Arctic temperatures Longer ocean transport season and more ice-free ports in northern regions Possible availability of a Northern Sea Route or a Northwest Passage Longer ice-free shipping season and increased access to more ice-free ports and resources in remote areas Longer season for barge transport
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Potential Impacts of Climate Change on U.S. Transportation Potential Climate Change Impacts on Marine Transportation Adaptation Options Operations and Interruptions Infrastructure Changes in Operations Changes in Infrastructure Design and Materials Other Temperature: later onset of seasonal freeze and earlier onset of seasonal thaw Extended shipping season for inland waterways ( especially the St. Lawrence Seaway and the Great Lakes) due to reduced ice coverage Increases in summer load restrictions Design of shallower-bottom vessels for seaway travel More dredging, but environmental and institutional issues Shifts to other transportation modes Sea level rise, added to storm surge More severe storm surges, requiring evacuation Changes in harbor and port facilities to accommodate higher tides and storm surges Reduced clearance under bridges Impacts on navigability of channels: some will be more accessible ( and farther inland) because of deeper waters, while others will be restricted because of changes in sedimentation More frequent bridge openings to handle shipping Raising of dock and wharf levels and retrofitting of other facilities to provide adequate clearance Protection of terminal and warehouse entrances Elevation of bridges and other structures More dredging of some channels Raising or construction of new jetties and seawalls to protect harbors
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Potential Impacts of Climate Change on U.S. Transportation Precipitation: increase in intense precipitation events Increases in weather-related delays Impacts on harbor infrastructure from wave damage and storm surges Changes in underwater surface and silt and debris buildup can affect channel depth Strengthening of harbor infrastructure to protect it from storm surge and wave damage Protection of terminal and warehouse entrances from flooding More dredging on some shipping channels Precipitation: increases in drought conditions for some regions Impacts on river transportation routes and seasons Restrictions on shipping due to channel depth along inland waterways and on other river travel More dredging on some shipping channels and harbors Release of water from upstream sources Shifts to other transportation modes Precipitation: changes in seasonal precipitation and river flow patterns Periodic channel closings or restrictions if flooding increases Benefits for safety and reduced interruptions if frozen precipitation shifts to rainfall Changes in silt deposition leading to reduced depth of some inland waterways and impacts on long-term viability of some inland navigation routes Restrictions on shipping due to channel depth along inland waterways and on other river travel More dredging on some shipping channels
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Potential Impacts of Climate Change on U.S. Transportation Potential Climate Change Impacts on Marine Transportation Adaptation Options Operations and Interruptions Infrastructure Changes in Operations Changes in Infrastructure Design and Materials Other Storms: more frequent strong hurricanes (Category 4–5) Implications for emergency evacuation planning, facility maintenance, and safety management Greater challenge to robustness of infrastructure Damage to harbor infrastructure from waves and storm surges Damage to cranes and other dock and terminal facilities Emergency evacuation procedures that become more routine Hardening of docks, wharves, and terminals to withstand storm surge and wave action
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Potential Impacts of Climate Change on U.S. Transportation ANNEX 5-1C Potential Climate Changes, Impacts on Air Transportation, and Adaptation Options Potential Climate Change Impacts on Aviation Adaptation Options Operations and Interruptions Infrastructure Changes in Operations Changes in Infrastructure Design and Materials Other Temperature: increases in very hot days and heat waves Delays due to excessive heat Impact on lift-off load limits at high-altitude or hot-weather airports with insufficient runway lengths, resulting in flight cancellations or limits on payload (i.e., weight restrictions), or both More energy consumption on the ground Heat-related weathering and buckling of pavements and concrete facilities Heat-related weathering of vehicle stock Increase in payload restrictions on aircraft at high-altitude or hot-weather airports Increase in flight cancellations Development of new heat-resistant runway paving materials Extension of runway lengths at high-altitude or hot-weather airports, if feasible Temperature: decreases in very cold days Changes in snow and ice removal costs and environmental impacts from salt and chemical use Reduction in need for deicing Reduction in snow and ice removal Reduction in airplane deicing
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Potential Impacts of Climate Change on U.S. Transportation Potential Climate Change Impacts on Aviation Adaptation Options Operations and Interruptions Infrastructure Changes in Operations Changes in Infrastructure Design and Materials Other Fewer limitations on ground crew work at airports, typically restricted at wind chills below −29°C (−20°F) Temperature: increases in Arctic temperatures Thawing of permafrost, undermining runway foundations Development of new runway paving materials Major repair of some runways Relocation of some landing strips Temperature: later onset of seasonal freeze and earlier onset of seasonal thaw Sea level rise, added to storm surge Potential for closure or restrictions for several of the top 50 airports that lie in Inundation of airport runways located in coastal areas Elevation of some runways Construction or raising of protective dikes and levees
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Potential Impacts of Climate Change on U.S. Transportation coastal zones, affecting service to the highest-density populations in the United States Relocation of some runways, if feasible Precipitation: increase in intense precipitation events Increases in delays due to convective weather Storm water runoff that exceeds the capacity of collection systems, causing flooding, delays, and airport closings Implications for emergency evacuation planning, facility maintenance, and safety management Impacts on structural integrity of airport facilities Destruction or disabling of navigation aid instruments Runway and other infrastructure damage due to flooding Inadequate or damaged pavement drainage systems More disruption and delays in air service More airport closures Increases in drainage capacity and improvement of drainage systems supporting runways and other paved surfaces Precipitation: increases in drought conditions for some regions Decreased visibility at airports located in drought-susceptible areas with potential for increased wildfires
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Potential Impacts of Climate Change on U.S. Transportation Potential Climate Change Impacts on Aviation Adaptation Options Operations and Interruptions Infrastructure Changes in Operations Changes in Infrastructure Design and Materials Other Precipitation: changes in seasonal precipitation and river flow patterns Benefits for safety and reduced interruptions if frozen precipitation shifts to rainfall Inadequate or damaged pavement drainage systems Increases in drainage capacity and improvement of drainage systems supporting runways and other paved surfaces Storms: more frequent strong hurricanes (Category 4-5) More frequent interruptions in air service Damage to landside facilities (e.g., terminals, navigation aids, fencing around perimeters, signs) Hardening of terminals and other facilities