Potential Impacts of Climate Change on U.S. Transportation Special Report 290 (2008) / Chapter Skim
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4 Challenges to Response
4 Challenges to Response
Pages 124-147
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From page 124... ...
. Highways, bridges, and public transportation infrastructure are owned and operated by state and local governments.1 Major funding for capital improvements -- and in the case of public transportation, rolling stock (e.g., transit buses, railcars)
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From page 125... ...
Ports and terminals Infrastructure State and local governments, Public and private funding independent authorities, and private entities Vessels Privately owned and operated NA Air Transportation Infrastructure Local governments and Federal funding, supplemented independent authorities with state and local grants and passenger facility charges Vehicle fleet Privately owned and operated NA Note: NA = not applicable. a The exceptions are highways on federal lands and private toll roads.
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From page 126... ...
Many airport capital improvements are federally funded, supplemented with state and local grants and passenger facility charges. In sum, decision making in the transportation sector is a shared responsibility among many governmental owner–operators and the pri vate sector, largely decentralized, and modally focused.
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From page 127... ...
Opportunities for adaptation -- for example, elevating a bridge to accommodate expected sea level rise -- are fewer for longer-lived facilities, which are rehabilitated or retrofitted at much longer intervals. In practice, many transportation facilities perform well beyond their design lives.
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From page 128... ...
Below is a brief summary of the planning process for publicly and privately owned infrastructure and the implications for addressing climate change. Publicly Owned Infrastructure Planning and investment decisions for publicly owned land transporta tion infrastructure are made within the framework and requirements defined by the planning provisions contained in legislation; codified in Title 23, U.S.C.; and most recently amended in August 2005 by the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users, known as SAFETEA-LU.
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From page 129... ...
Pipeline companies conduct market forecasts looking ahead 5 years at most. Planning for capital improvements follows the normal private-sector capital budgeting process (i.e., project analysis using present value calculations over asset lifetimes, minimum expected rates of return for project selection, and annual capital budgets)
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From page 130... ...
states. Others are organizing to achieve better management of traffic congestion and incident control by establishing transportation manage ment centers.9 Climate changes are expected to affect transportation primarily through climate extremes, such as more severe tropical storms and flooding from intense rainfall.
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From page 131... ...
Thus, many transportation planners perceive that impacts of climate change will be experienced well beyond the time frame of their longest-term plans, not realizing that climate changes are already occurring and that investment decisions made today will affect how well the infrastructure accommodates these and future changes. Treatment of Uncertainty The issue of climate change introduces uncertainties with which transportation planners are unfamiliar and uncomfortable.
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From page 132... ...
Sea level rise and flooding from intense precipitation, for example, can affect individual transportation facilities, but they are also likely to have widespread impacts requiring the response of multiple infrastructure providers. Some climate changes, such as more frequent intense tropical storms (Category 4–5 hurricanes)
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From page 133... ...
Over time, for example, roads, rail lines, and airport runways in low-lying coastal areas may become casualties of sea level rise, ultimately requiring relocation or expensive protective measures (e.g., levees, which themselves would be subject to catastrophic failure, as was experienced during Hurricane Katrina)
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From page 134... ...
Others opted for a literal interpretation of SAFETEA-LU's planning guidance, which does not require consideration of climate change, or pointed to federal policies that allow replacement of facilities only as they are currently designed, preventing consideration of design modifications that could provide for adaptation to potential climate change impacts (e.g., elevated bridges to accommodate sea level rise, storm surge, and wave action) .11 Some officials interviewed believed that Federal Highway Administration regulations prevented them from considering any changes that would extend beyond the time horizon of their long-range plans.12 Still others identified limited current funding that, in combination with uncertain ties about the rate and timing of projected climate changes, disinclines planners to give more attention to the issue.
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From page 135... ...
Climate scientists should be encouraged to develop information on transportationrelevant climate changes that is as detailed as possible. Transportation professionals also have a role to play in helping to define what information about climate change they need, such as temperature and precipitation thresholds, climate conditions that create unacceptable performance outcomes, and the like.
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From page 136... ...
Adapting risk based approaches to account for climate change poses new challenges. First, historical experience will not be a reliable predictor of future climate conditions.
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From page 137... ...
The exceptions to the "no collapse" requirement were 750 structures for which the highest level of performance was desirable to protect the substantial investment in these major structures and ensure that they would remain in service after a major seismic event to provide access for emergency responders. The 11 major toll bridges, including the San Francisco–Oakland Bay Bridge, were handled separately because their complexity necessitated a time-consuming dynamic analysis.
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From page 138... ...
The bridges identified through this process are prioritized and added to the program as required. State and local governments and private infrastructure providers could adopt a similar approach for identifying and screening critical infrastructure relative to projected climate changes.
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From page 139... ...
State and local transportation officials could adopt a similar approach to assess how climate change may affect transportation assets and develop appropriate adaptation responses and investment strategies. To begin, they might ask the following questions: • Which projected climate changes are most relevant for their region?
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From page 140... ...
In the California situation, the Loma Prieta earthquake focused attention on the need for seismic retrofit of many of the bridges throughout the state to avoid catastrophic failure and loss of life from such an event in the future. With climate changes, however, the impacts will not always be as unambiguously attributable to those
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From page 141... ...
First, transportation professionals must recognize climate change as a credible and important problem so that champions will emerge to bring attention to the issue and to make collaboration with climate scientists and meteorologists a priority. Second, addressing climate change requires a longer-term perspective and recognition that investment decisions made today, particularly about the location of transportation infrastructure, help shape long-term development patterns and markets well beyond the 30-year time frames of many public-sector capital improvement plans and private-sector capital budgeting analyses.
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From page 142... ...
The results of such assessments should be presented in a form that can be communicated to senior management and elected officials as a prudent action program, and provision should be made for adjustments as new knowledge becomes available. Finally, addressing the impacts of climate change that require regional and multistate responses is likely to entail developing new coalitions and organizational arrangements.
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From page 143... ...
For instance, the risk of the loss of a coastal road due to a storm surge would be the likelihood of a storm surge rising high enough to inundate the road, multiplied by both the dollar cost of replacing the flooded road and the costs of the economic disruption during the time the road was unusable. In principle, transportation managers could use this risk definition to thoroughly assess the risks posed by climate change for their system.
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From page 144... ...
for each asset in the transportation system. Carrying out this analysis would provide transportation managers with an estimate of their total risk and the most important sources of that risk.
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From page 145... ...
As discussed in Chapter 2, some hazard estimates from such models, in particular, estimates of the likelihood of extreme events, may be less reliable than others. The final reason that a comprehensive probabilistic risk assessment would prove difficult is that many transportation assets are long-lived, many of the most important impacts of climate change are expected to increase over time, and future transportation managers may take steps that can reduce (or perhaps unintentionally increase)
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From page 146... ...
CLIMATE RISK ASSESSMENT FOR TRANSPORTATION MANAGERS IN PRACTICE The above factors -- lack of complete data, uncertainty about the reliabil ity of projections of future climate change, and uncertainty about the actions future managers will take to reduce the vulnerability and increase the resilience of a transportation system -- make it difficult to conduct a comprehensive probabilistic risk analysis for a regional transportation system. In future years, more comprehensive planning frameworks can be expected to come into use that will help transportation managers inte grate consideration of exposure, vulnerability, resilience, and adaptation factors.
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From page 147... ...
Engineers commonly incorporate safety factors into designs or design standards to account for unforeseen events or abnormal forces on structures. Similarly, transportation managers should recognize that it may be difficult for climate change projections to distinguish a future 100-year storm from a future 500-year storm, or that estimates of the likelihood that sea level rise will exceed 1 m by 2100 may change significantly in the years ahead.
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