The impact of climate change on roads
The US road sector is one of the nation's critical infrastructure sectors, which is crucial to the functioning of its economy. The annual maintenance of this capital asset costs approximately $134 billion, derived from federal, state, and local governments. Climate change may pose a risk and an opportunity to the sector as the changes in climate conditions will influence the economics of road maintenance and construction (Chinowsky et al., 2013).
Climate change can increase road maintenance and/or construction or decrease costs in some areas. For example, the cost increase might happen due to the tremendous risk of climate change effects, as the Fourth National Climate Assessment proclaims that "warmer temperatures, sea level rise, and extreme weather will damage property and critical infrastructure" (Garcia, 2020). On the other hand, cost reduction might happen when changes in freeze-thaw lessen the frequency and annual costs of resealing US paved roads (Chinowsky et al., 2013). In general, climate change, if left unchecked, will drastically increase the yearly service costs of US paved and unpaved roads by $785 million (in discounted 2050 US$) and by $2.8 billion (in undiscounted 2050 US$) (Chinowsky et al., 2013). Thus, it is crucial to find solutions to the impact of climate change on US roads.
Adapting to road harm
From a policy and economic perspective, adaptation can assist in avoiding the adverse impacts of climate change on US roads. Two types of adaptation apply to this crucial infrastructure sector: reactive adaptation and proactive adaptation.
Reactive adaptation is characterized as a scenario in which infrastructure planners respond to climate-change impacts by repairing climate-damaged infrastructure but not taking further actions to reduce or prevent future climate-change impacts on roads. Proactive adaptation is a scenario where the infrastructure planners intentionally take adaptive measures to avoid infrastructure repair costs connected to future climate change impacts. Such actions usually incorporate tradeoffs between higher upfront expenditures for possible future savings and benefits (Neumann et al., 2019).
Proactive adaptation can take many forms. Ralston (2022) proclaims, “The only solution it seems – short of billions of delivery drones, flying trucks and teleportation – is to fix the way roads are made.” For example, in California, Los Angeles started using special gray paint CoolSeal, which keeps pavements cooler (Leary, 2017). In some states, nature-based solutions are critical as coastal highway infrastructure adaptation strategies. These solutions, which rely on enhanced or existing landscapes, help reduce the impact on coastal highways from storm surges, rising sea levels, and other types of flooding (Buckingham & Torossian, 2021).
Which reigns supreme?
The projections for the US road sector, based on two pathways, Representative Concentration Pathway (RCP) 8.5 (as a higher GHS emissions scenario) and RCP 4.5 (as a lower GHG emissions scenario), show that the costs under the Reactive Adaptation scenario (RCP8.5 scenario) increase by 2090. The opposite occurs under the Proactive Adaptation scenario (RCP 8.5), meaning that planning for climate change-connected damages may decrease future costs in the road sector (Neumann et al., 2019). Martinich and Crimmins (2019) also attest to the economic superiority of proactive adaptation by comparing the reduction in annual average costs in 2090 (billions of undiscounted 2015 US$) between reactive and proactive adaptation.
Damages avoided by proactive adaptation show that proactive adaptation measures can substantially lessen the climate-related damages on the US road sector. Furthermore, proactive adaptation, as a "remarkably cost-effective insurance policy," and greenhouse gas emissions mitigation provide the most prominent benefits (Neumann et al., 2019). For example, Caltrans approved the usage of low-carbon cement to upgrade California's highway system. Switching to low-carbon cement (Portland limestone cement) may reduce carbon dioxide emissions by 28,000 tons/year (Caltrans, 2022). Therefore, proactive adaptation, especially with mitigation efforts, is the best solution to the climate change-related impact on the US Road sector.
Applying the Benefit-Cost Analysis (BCA) is beneficial for policymakers in deciding the economic pathways for financing proactive adaptation. Circular A-4 describes BCA as essential for evaluating quantitative and qualitative benefits and costs for US citizens and residents (The White House, 2003). As mentioned earlier, the baseline scenario is connected to the lack of response to climate change-related impacts on roads. This "no-action" will drastically increase the annual service costs of US paved and unpaved roads by $785 million (in discounted 2050 US$) and by $2.8 billion (in undiscounted 2050 US$) (Chinowsky et al., 2013). According to Martinich & Crimmins (2019), the "vulnerability of current paved, unpaved, and gravel roads to future changes in temperature, precipitation, and freeze-thaw cycles is economically valued by costs of repair and rehabilitation” (p. 398). Neumann et al. (2019) further define the costs of proactive adaptation as 1) upfront capital costs of proactive road strengthening, 2) repair costs, and 3) delay costs due to proactive repairs and strengthening.
Currently, the financing available under the Bipartisan Infrastructure Law is the solution for proactive adaptation financing, hopefully, the first of many. For example, the Biden Administration announced PROTECT (Promoting Resilient Operations for Transformative, Efficient, and Cost-Saving Transportation) formula program ($7.3 billion from Bipartisan Infrastructure Law), which will start helping states to make transportation infrastructure more resilient to climate change (Department of Transportation, 2022). Another valuable program for proactive adaptation is the National Highway Performance Program under Bipartisan Infrastructure Law, which supports the National Highway System (NHS)’s resiliency initiatives against climate change-related impacts (Department of Transportation, 2022).
Proactive adaptation has economic, environmental, and social benefits as a solution for climate change's impact on the US road network. The economic benefits of proactive adaptation are related to protecting the entire transportation system, which supports the supply chain and economic output at national, regional, and local levels. A resilient road network can also ensure that people can get to their places of employment without interruption (Chinowsky et al., 2013; EPA, 2022). The environmental benefits of proactive adaptation come from using low-carbon innovative technologies that can prepare the US road network for climate change. Besides the examples above of gray paint and nature-based solutions, bio-binders, such as lignin, can be used instead of petroleum-based binders to stabilize the materials inside asphalt (Ralston, 2022). Such technologies can assist proactive adaptation and mitigation goals by reducing the carbon footprint. Lastly, social benefits of proactive mitigation represent the reduction of safety risks to people on climate change-impacted roads, support of environmental justice and equity goals by supporting low-income, rural, and indigenous communities’ access to essential services (EPA, 2022), and indirect health benefits from the usage of low-carbon technologies as proactive adaptation solutions for the US road network.
The article describes the impact of climate change on US roads and presents proactive adaptation as the best solution for the problem. It also describes the costs and benefits (economic, environmental, and social) of proactive adaptation compared to the "no-action" scenario when climate change is unchecked. This analysis proves that despite initial high costs under the proactive adaptation scenario, the net benefits (the value of proactive adaptation benefits minus the proactive adaptation costs) justify proactive adaptation as the best solution for ensuring the resiliency of the US road network and the US economy in the face of rapidly increasing climate risks.
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Caltrans (2022, January 25). Caltrans approves the use of low-carbon cement to help combat climate change. Caltrans. https://dot.ca.gov/news-releases/news-release-2022-003
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