Adaptation Research and Development
The mitigation efforts described in the previous chapter are necessary in reducing transportation’s future contributions to climate change and energy consumption. The greenhouse gases (GHGs) emitted by industrialization over the past century, however, will persist for decades because of the long-lived nature of some GHGs and will result in temperature rise and associated climate change regardless of future mitigation. Thus it is necessary to plan for adapting to climate change.
The report prepared by a National Research Council Committee, Special Report 290: Potential Impacts of Climate Change on U.S. Transportation (TRB 2008), identified the kinds of changes that are likely to occur and recommended actions that the transportation community and others should take to prepare. This chapter draws heavily on the findings and recommendations made in that report. The committee also commissioned a paper by McNeil (2009) to build on the recommendations of Special Report 290 and develop a detailed framework for an adaptation research and development program. This chapter draws on McNeil’s paper but does not follow it in all details.
This chapter first provides a brief summary of the main findings and recommendations of Special Report 290, with emphasis on those relating to research. It then outlines a program that responds to those findings and recommendations: it identifies research topics, estimates the cost of the research, and identifies criteria for a successful research program.
EXPECTED CLIMATE IMPACTS ON TRANSPORTATION INFRASTRUCTURE AND RESPONSES
Impacts and Consequences
Special Report 290 identifies five future climate changes relevant to transportation infrastructure and operations:
Increases in very hot days and heat waves,
Increases in Arctic temperatures,
Rising sea levels,
Increases in intense precipitation events, and
Increases in hurricane intensity.
The committee that prepared the report emphasized that, contrary to the general perception that climate change will result in gradual changes in temperature and sea level rise in coming decades, the key concerns for transportation are temporary, abrupt, and unanticipated extremes of temperature, precipitation, and storm intensity that could occur at any time and that will become more frequent.
The committee that prepared Special Report 290 concluded that the greatest climate change impact on North American infrastructure will likely be flooding of coastal roads, railways, transit systems, and runways because of global rising sea levels coupled with storm surges, exacerbated in some locations by land subsidence. Roughly half of the U.S. population resides in coastal counties; hence, a substantial share of the nation’s population and infrastructure is at risk. Among the challenges posed in responding to climate change are deep uncertainties about its impacts as well as about the effectiveness of various adaptations (Dewar and Wachs 2006).
For example, climate change will alter weather patterns so that historical records will no longer be reliable guides to 100- and 500-year floods. Such rare events are the basis of designing facilities to withstand maximum likely storms. They will become more frequent than history suggests, but climate scientists are unable to forecast where and when such changes will occur at the temporal and spatial scales that planners, designers, and operators of infrastructure require. The limited ability to predict the location and frequency of more intense storms will result in higher degrees of uncertainty with regard to severe outcomes than trans-
portation engineers are accustomed to. Intelligently managing infrastructure in these circumstances will require new tools that incorporate rather than attempt to exclude uncertainty (Dewar and Wachs 2006).
Identified Adaptation Responses
Special Report 290 made the following recommendations that pertain to this chapter:
Transportation officials at all levels of government and in the private sector should inventory potentially vulnerable critical assets.
Transportation officials should incorporate climate change into their long-range plans for new facilities and maintenance.
Transportation officials should rely on more probabilistic techniques to guide decisions that weigh the cost of upgrading or protecting assets against the risk and consequences of failure.
Research programs should invest in developing monitoring technologies that can measure stresses and strains on key infrastructure assets and provide warning of pending failures.
Transportation professional associations should develop procedures to identify and share best practices in managing assets.
The committee also laid out a decision framework for transportation professionals to use in addressing impacts of climate change on U.S. transportation infrastructure:
Assess how climate changes are likely to affect various regions of the country and modes of transportation.
Inventory transportation infrastructure essential for maintaining network performance in light of climate change projections to determine whether, when, and where the impacts could be consequential.
Analyze adaptation options to assess the trade-offs between making the infrastructure more robust and the costs involved. Consider monitoring as an option.
Determine investment priorities, taking into consideration the criticality of infrastructure components as well as opportunities for multiple benefits (e.g., congestion relief, removal of evacuation route bottlenecks).
Develop and implement a program of adaptation strategies for the near and long terms.
Periodically assess the effectiveness of adaptation strategies and repeat Steps 1 through 5.
R&D is needed to provide tools and guidance for carrying out each of the first five steps in this decision framework. A program to address these and other adaptation needs is developed in the next section.
R&D TO GUIDE ADAPTATION
McNeil (2009) identifies a number of research initiatives that should be conducted early in the program to serve as foundations for policy guidance to decision makers and practitioners as well as for subsequent R&D. These foundational topics derive from the research that needs to be done to assist transportation officials in carrying out the recommendations and decision framework in Special Report 290.
Identification of Vulnerable Assets and Locations
The first step recommended in Special Report 290 is for transportation officials to identify infrastructure potentially threatened by climate change. The task is more difficult than may be apparent because the severity of impact can be increased by a confluence of events. In the Gulf Coast region, for example, storm surges will be compounded by the land subsidence already occurring, increased wind speeds from more intense storms, and heavier precipitation. These interacting effects require careful and extensive analysis, as illustrated by the Global Change Research Program study of Gulf Coast infrastructure vulnerability (Savonis et al. 2008). The need to consider and portray the vulnerability of infrastructure in probabilistic terms adds to the complexity (Meyer 2006). Furthermore, every region will be affected in its own way. In Southern California, for example, the sea level may rise; in addition, the frequency of drought and dry winds may increase, which in turn could increase the frequency of brush fires and smoke hazards on freeways and subsequent mudslides in rainy seasons that can inundate and wash out roads.
The objective of this research would be to develop a process for identifying assets and locations that are vulnerable to climate change. Developing the process will necessarily involve climate change scientists, experts in risk assessment, and engineers. Once a methodology has been developed, it could be adapted to and replicated in other regions.
Identification of Opportunities for Adaptation of Specific Facilities
Once vulnerable assets have been identified, policy makers will need a range of options for responding, which entails the conduct of a comprehensive review of policy, engineering, and other options for addressing risk. The objective would be to develop a database of options for specific facilities and regions that transportation officials could draw on.
Understanding Changes in the Life Span of Facilities Caused by Climate Change
The expected life span of facilities can be changed by climate influences such as heat, drought, wind loading, and flooding. Understanding infrastructure life spans is a challenging problem even in the absence of the effects of climate change. Guidance may initially have to rely on judgment while this area of more basic research develops.
Understanding the Modes and Consequences of Failure
Better understanding of potential modes of failure and its consequences is key to informing the evaluation of options. Failure in this sense is not necessarily a catastrophic failure; it could be structural, functional, or economic. This research would summarize available understanding, both experiential and theoretical, to provide guidance on what transportation officials would need to prepare for.
Assessing the Risks, Costs, and Benefits of Adaptation
Once assets have been identified as vulnerable to climate change, possible effects on their future performance have been assessed, and options for responding to risk have been arrayed, policy makers need guidance on the costs and benefits of the various options. The objective of this research area would be to develop a framework for producing and
refining estimates of costs and benefits. Such estimates may have to rely on judgment initially, but they should be refined with experience and research.
Models and Tools to Support Decision Making
McNeil defines this area as an essential component of her applied research agenda, but the committee views this research area as a cornerstone of adaptation planning and analysis. The necessity of managing uncertainty in many dimensions of decision analysis transforms this from an applied to a foundational topic for several reasons. The timing, location, and severity of climate change are uncertain. The costs and benefits of adaptation options may be definable with less uncertainty, but the estimates will not be precise. The costs of many measures to reduce the risk of failure—raising bridges; relocating highways, transit stations, or rail lines; adding berms and levees—could be high while the risks themselves will be uncertain and difficult to quantify. Furthermore, policy makers will have to weigh the cost of reducing risk against the opportunity cost of applying those resources elsewhere. Analysis tools appropriate for policy problems that encounter such fundamental uncertainty are being developed (Lempert et al. 2003; Dewar and Wachs 2006). Extension of these approaches to transportation adaptation will require fundamental rather than simply applied research.
Monitoring and Sensing
Another area that McNeil defines as applied is considered by the committee to be a cornerstone of adaptation. In many cases, monitoring condition and performance will probably turn out to be the smartest “no regrets” approach. Sensors for monitoring infrastructure condition and performance are already in use. Advances in technology allow sensors to report on water pressures, saturated soils, thermal and wind stresses, and scouring of bridge supports. As McNeil (2009) points out, however, the “challenge lies in how, where, and when to deploy the sensors and how to interpret the signals and then how to communicate the information provided by the sensors.” To this challenge can be added the need to improve understanding of what to measure and how to maintain the sensor systems cost-effectively. Sensors are already in place to monitor
scour of critical bridge foundations, but understanding of which phenomena to monitor can be improved, and reliable and more cost-effective sensors are needed (Hunt 2009).
McNeil (2009) identifies a number of applied research topics that follow, for the most part, categories of research typical in transportation civil engineering:
Planning and environmental decision making,
Design standards and practices,
Renewal and rehabilitation,
New infrastructure to support mitigation measures,
Long-range planning related to transportation and land use,
The influencing of land use decisions, and
The funding of adaptation.
These topic areas are described briefly by McNeil (2009) and are not repeated here. McNeil’s suggestions for applied research in each of these topic areas, however, might be best considered as placeholders. As she emphasizes, expert and practitioner stakeholders need to be intimately involved in the development of a research agenda to ensure its relevance. If a research program for adapting transportation to climate change is funded, a necessary first step would be to develop a detailed research agenda in these areas through extensive stakeholder engagement. One area not specifically referenced by McNeil that should be incorporated into the applied R&D agenda is the principles of “green infrastructure” design (EPA 2008; Gill et al. 2007). Green infrastructure design, among other things, attempts to minimize urban water runoff through strategies to better capture or divert water from heavy rains into floodplains or catchment areas. Improving the permeability of pavements and wider use of grassy medians, for example, could be part of a larger strategy to minimize flooding.
Supportive activities that McNeil (2009) foresees as part of an adaptation research program include the following:
An information clearinghouse to facilitate exchange of relevant scientific information among researchers in different fields and disciplines and across levels of government;
An ongoing dissemination activity to share the results of the research, which would include education and outreach to the public and decision makers;
Proactive engagement of stakeholders in project scoping, research, evaluation, and dissemination;
Coordination and analysis of cross-cutting issues; and
Evaluation of ongoing and completed research to manage and direct the program.
The section of this chapter on research program design expands on the extensive role of stakeholders envisioned by McNeil.
McNeil’s schedule begins with foundational research and supporting research activities, with most of the applied research gearing up after the second year and some even later. Most of the foundational research would be completed by the fifth year, but the more basic research on understanding facility life spans and the costs and benefits of adaptation would extend for the full 20-year period. The committee prefers a different schedule, with the greatest initial emphasis on the foundational research elements that build up to the tools and methods for evaluating vulnerabilities and for assisting in decision making.
RESEARCH PROGRAM DESIGN
To ensure the credibility of the research program and to maximize quality control, the conduct of the research should be open to all potential research organizations, research teams should be selected on the basis of
merit as judged by peers, and completed research should be subject to peer review.
McNeil stresses throughout her paper the importance of involving stakeholders in development and execution of an adaptation research program:
Stakeholder engagement—proactively engage stakeholders in project scoping, research, dissemination and communication to ensure that products meet the needs of the audience, ongoing research is not ignored, and unintended consequences are minimized (Natural Resources Canada 2004). In the words of the California White paper on climate change (Luers and Moser 2006) “collaborative and participatory research” should be encouraged. Stakeholder engagement also includes education of and outreach to the public and decision makers focusing on climate change science, potential impacts and the importance of action.
The stakeholder involvement that McNeil suggests for adaptation research is modeled on the processes used by the cooperative research programs managed by the Transportation Research Board and other applied research programs, such as those of the Association of American Railroads and the Electric Power Research Institute. In these programs, expert and practitioner stakeholders are engaged in suggesting research topics (“problem statements”), developing the problem statements into requests for proposals, providing merit review of submitted proposals, monitoring research as it is conducted, and evaluating research when it is completed. The availability of an expert staff to scope out and manage the contracting and project delivery process, open competition to find the best research teams, selection of proposals by expert peers, and peer review are important in ensuring quality control.
Climate change is already occurring, and GHGs persist in the atmosphere for long periods. For these reasons, adaptation has become a necessity. A research program based on the recommendations in Special Report 290 is needed, with emphasis on development of decision tools
incorporating probabilistic outcomes and options to help state and local officials make prudent decisions about adapting infrastructure to climate change. Because of the diversity of officials responsible for transportation infrastructure and the need to ensure the relevance of the research to varied perspectives, stakeholder involvement is critical in developing an effective applied research agenda and carrying out an adaptation research program. Stakeholder involvement at all levels, open competition, merit review, and peer review are important criteria for the success of these research activities.
EPA Environmental Protection Agency
TRB Transportation Research Board
Dewar, J. A., and M. Wachs. 2006. Transportation Planning, Climate Change, and Decision-making Under Uncertainty. Transportation Research Board of the National Academies, Washington, D.C. http://onlinepubs.trb.org/onlinepubs/sr/sr290DewarWachs.pdf. Accessed Sept. 15, 2009.
EPA. 2008. Managing Wet Weather with Green Infrastructure: Action Strategy. http://www.epa.gov/npdes/pubs/gi_action_strategy.pdf. Accessed Aug. 8, 2009.
Gill, S. E., J. F. Handley, A. R. Ennos, and S. Pauleit. 2007. Adapting Cities for Climate Change: The Role of the Green Infrastructure. Built Environment, Vol. 33, No. 1, pp. 115–133.
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McNeil, S. 2009. Adaptation Research Programs and Funding. Transportation Research Board of the National Academies, Washington, D.C.
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Savonis, M., B. Burkett, and J. Potter (eds.). 2008. Impact of Climate Variability and Change on Transportation Systems and Infrastructure—Gulf Coast Study. Final Report of Synthesis and Assessment Product 4.7. Global Change Research Program, U.S. Department of Transportation. http://www.climatescience.gov/Library/sap/sap4-7/final-report/. Accessed April 25, 2009.
TRB. 2008. Special Report 290: Potential Impacts of Climate Change on U.S. Transportation. National Academies, Washington, D.C.