Key uncertainties, research needs, and information gaps (Climate Change and Urban Transportation Systems)

Many levels of uncertainties drive research needs and define information gaps, these range from the identification and degree of certainty of climatic factors and consequences specific to transportation to the performance of transportation technologies for both mitigation and adaptation and their relationship to other infrastructure.

The IPCC (2007a) has identified three macro-scale uncertainties in assessing transportation adaptation and mitigation potentials for any city. The first uncertainty relates to the international price of oil and associated demand for alternate fossil fuels. The second uncertainty relates to the pace of innovation in alternate energy sources such as biofuels, externalities associated with their large-scale consumption: food prices, water shortages, and the like, and batteries. The third uncertainty is the timeline on which policies on greenhouse gas emissions reduction will be adopted and implemented by developed and developing countries.

Other critical issues pertain to the availability of, and access to, information at the international level. First is the lack of data on transport energy consumption in developing countries now and projected for the future, and thus uncertainties in the magnitude of emissions that will occur as a result of energy consumption overall and the use of alternatives to oil. With a few exceptions, the geographical focus in the present research is on developed country transport systems, especially in the United States and Europe. There is a gap in the literature on the implications of climate change on urban transport policy and planning in developing counties.

Second is the absence of a broad framework to assess global opportunities and costs of reducing greenhouse gas emissions in the transportation sector. Consistency and coordination is needed among international agencies in their support of climate-friendly transportation projects and longer-term goal setting. The availability and distribution of information about adaptation and mitigation vary from local to global levels in both developed and developing countries, and this variability contributes to problems of coordination and consistency.

Potter and Savonis (2003) and Hyman et al. (2008) outline some of the important research needs and challenges to prepare transportation system for the impacts of climate change. Regional and local-scale climate projection models that incorporate unique attributes of the urban transportation systems are lacking. But downscaled assessments are a prerequisite for transportation planners to identify facilities and locations that are vulnerable to the impacts of climate-related events. Further, impacts need to be disaggregated into implications for operations, maintenance, and safety of transportation systems for the short- and long-term effects.

City managers require new tools to evaluate the benefits and costs of a range of response options that incorporate future uncertainties into modal choices, sitting infrastructure, design and engineering standards, and the like. For example, "[it] is unlikely that infrastructure improvements such as realignment of roadways, many of which run through river valleys, can be justified on a cost-benefit basis" in the Boston area (Tufts University, 2004, p.155). Additionally, there is a need for improved techniques for assessing risk and integrating climate information into transportation planning and management within the broader context of city planning and management.

On top of these uncertainties and gaps in knowledge are those within climate science itself, discussed extensively in other topics. One example is the extent of ice melting and its impact on sea level rise at specific geographic locations. Another is the intensity and frequency of storms in light of the difficulty of predicting cloud formation and, more recently, the influence of changes in monitoring protocols of storm frequency and intensity. These climate uncertainties combine with uncertainties associated with the consequences of climate conditions specifically for transportation at any given place and time. Finally, the performance of technologies in reducing the adverse consequences adds another layer of uncertainties which reflects gaps in knowledge. For example, construction standards and the designs of transportation infrastructure will adapt to climate change impacts depending on environmental factors that affect the strength of the new systems.

Research gaps for adaptation include the need for knowledge on how climate hazards will affect transport infrastructure, including the engineering design and performance standards for urban transport systems and associated infrastructure assets. Furthermore, research on relationships between climate hazards and social and economic impacts related to urban transport systems is much needed. For instance, research on quantifying the expected impacts of climate change on types of transport systems and their users is lacking. Further, there is need for research analyzing climate impacts on planned investments in the transport sector, as most research focuses on climate impacts on existing transportation systems. Finally, intra-and-inter sectoral co-benefits of adaptation and mitigation need attention (Lindquist, 2007). For example, transportation is dependent on electric power and telecommunications as well as water and environmental services and will be affected by adaptation and mitigation efforts in these sectors. Likewise, changes in the the delivery of goods and services for transportation industry supply chains will affect the transportation systems as well.

Research needs and information gaps for mitigation include the evaluation of specific mitigation policies for effectiveness in reducing greenhouse gas emissions from transport in a city; and economic costs of mitigation in the urban transport sector with careful consideration of areas in which mitigation measures for transport might conflict with others and actually contribute to greenhouse gas rather than reducing it. For instance, there is a need for comparative studies on the cost of producing and switching to clean fuels and new vehicle technology so as to allow urban transport planners and stakeholders to make informed choices on new technology options for low-emission transportation systems. Finally, as with adaptation, the feasibility for mitigation of various options in light of the extent and role of the interdependencies within various transportation sectors (Lindquist, 2007) and between the transportation sectors and other sectors and activities with which transportation interacts or affects must be studied. For instance, there is a need for further research on methodologies for standardizing inventories from transportation emissions and criteria for including emissions from national, regional, and local transport systems that extend beyond the jurisdiction of cities and are interconnected with other sectors such as telecommunications, energy, and water. There is also a need to explore the interaction between the energy intensity resulting from modal choices and their interaction with types of land uses and other urban infrastructure systems.

Thus, large uncertainties will continue to exist and new ones will continue to emerge as summarized above in the science and technology that justify and support moving forward on both adaptation and mitigation. In light of this, some have argued that the key strategy is to move forward on reasonably robust measures and to evaluate the performance of those measures over time, rather than to await the resolution of uncertainties before acting (Dessai et al., 2009). For transportation, adopting such a policy with its accompanying strategy suggests moving ahead with a multi-pronged approach that emphasizes the availability and use of multiple modes of travel that avoid greenhouse gas emissions and at the same time are flexible and resilient to the impacts of climate change, that is, made of more resistant materials and able to withstand potentially prolonged flooding and the intensity of storms.

Conclusions

Generally, public actions aim to anticipate and frame market-based urban development toward a more energy-efficient city. That can involve analyzing market dynamics – transport markets, real-estate markets, and housing markets – and integrating them in local urban planning. A challenge is to adopt a planning model that works to create dynamic middle- and long-term urban development trajectories, rather than static or "one-off" systems.

The combination of adaptation and mitigation policy instruments to be implemented for the urban transportation system is a city-specific issue combined with overarching global policies as a guide. Transport policies are easier to implement, but their potential to reduce greenhouse gases may be lower than for other activities. Land use policies can be stronger levers of action to reduce greenhouse gas emissions due to urban transportation, but they may be harder to implement.

For cities in developing countries, the challenge is more to keep their mixed land use and high-density settlements, and transport systems in which low-emission modes are still dominant, without compromising efforts for future economic development and urban poverty reduction, both of which rely on expanding effective and efficient transportation systems and associated modal choices.

Public education and effective communication on policies that aim to reduce greenhouse gas emissions are important aspects for successful promulgation of adaptation and mitigation policies in urban transportation systems. These efforts can emphasize local co-benefits in and seek to gain – and secure over the long-term -public support for these measures.

Finally, several elements have emerged for climate change adaptation and mitigation policies to be successful for urban transport planning and management. These include strong leadership and even championing climate change mitigation; an effective outreach and public education campaign; risk assessment, benefit-cost analysis, and management – particularly for adaptation; mainstreaming of climate concerns in transport planning and policymaking; higher-level government or international community provision of incentives to mainstream climate – not only through funding, but through international recognition as well; technology transfer; regional-local governance coordination; assessment of the capacity to act among all actors – all levels of government, private sector and individuals; and overall, attention to reduction in vehicle miles traveled through land use and other strategies that may accomplish this. Science-based policy is crucial.

Annex

Annex Table 6.1: Impacts of climate change on transportation.

Annex Table 6.1:

Annex Table 6.2: Indirect impacts of climate change as a result of direct impacts outlined in Annex Table 6.1.

Demographic impacts

UK Climate Impacts Programme Report on the West Midlands noted, "higher temperatures and reduced summer cloud cover could increase the number of leisure journeys by road." (Entec UK Ltd, 2004)

Security impacts

Increased shipping activities will raise security, ownership, maintenance, and safety concerns.