Transportation Resilience: Adaptation to Climate Change (2016)

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12 SESSION 1 Managing the Risk Gordana Petkovic, Norwegian Public Roads Administration, Oslo, Norway Rebecca Lupes, U.S. Department of Transportation, Washington, D.C., USA André van Lammeren, Rijkswaterstaat, Ministry of Infrastructure and the Environment, Netherlands Alan McKinnon, Kühne Logistics University, Hamburg, Germany Jennifer Jacobs, University of New Hampshire, Durham, USA Richard Wright, University of Maryland, College Park, USA Presentation of first Case sCenario: rising sea level Gordana Petkovic and Rebecca Lupes Gordana Petkovic and Rebecca Lupes presented the first scenario, which focuses on sea level rise and managing risks to the transport system. They noted that in this phase, agencies are working to prepare for future risks and threats. Although this scenario considers responses to sea level rise, the same approach to managing risks would be appropriate for flooding, landslides, and heat waves. Appendix B contains more information on this scenario. Petkovic discussed the observed annual sea level rise, up from 1.7 millimeters/year between 1901 and 2010 to 3.2 millimeters/year between 1993 and 2016, and noted the increasing rate of change. She described the global mean sea level rise from 2006 to 2100 as deter- mined by multimodal simulations showing changes relative to the period from 1986 to 2005. She noted that differences in sea level rise exist along the coasts of the world, and that these differences are related to local ocean temperature variations, salinity, currents, and subsidence or uplift of land. Subsidence is cause by the pumping of groundwater, oil and gas extraction, compression under heavy construction, and land use. She reported that subsidence adds to the relative sea level rise. She noted that postglacial rebound, which occurs in areas that were covered by ice during the last ice age, counteracts sea level rise. She commented that storm surges present a threat today that may increase in the future due to the expected increase in storm activity. She noted that sea level rise is affecting coastal areas in Europe and the United States. Petkovic introduced the two vulnerability studies that form the basis of this scenario. The first study focused on the U.S. Gulf Coast area, and the second study exam- ined the Languedoc–Roussillon region in France, which is located along the Mediterranean Sea. Lupes described the Gulf Coast case study, which cov- ered the area between Houston and Galveston in Texas and Mobile, Alabama, and New Orleans in Louisiana. Lupes pointed out that the low-lying Gulf Coast area is extremely vulnerable to sea level rise. She noted that petroleum extraction and sedimentation loss due to the channeling of the Mississippi River have exacerbated subsidence in some areas. Further, much of the coast is vulnerable to erosion and wetland loss from coastal storms. Lupes noted that the region is nationally significant, handling 60% of the nation’s petroleum imports and housing the largest concentration of marine freight facili- ties in the United States. It has several major urban cen- ters, including Houston, New Orleans, and Mobile. The area has an extensive intermodal transportation network that includes 17,000 miles of highway with 83.5 billion vehicle miles traveled and six Class I railroads. Fifty-six million passengers traveled through the three largest air- ports in the region in 2005. Lupes described a two-phased study of the impacts of climate change on the region’s transportation network

13S e S S i o n 1 : m a n a g i n g t h e r i S k conducted by the U.S. DOT. Phase I of the study, which was completed in 2008, examined the impacts of climate change at a broad regional scale from Houston to Mobile. Phase II was a more in-depth assessment of impacts and risks in Mobile. More information about the two phases of the study can be found at https://www.fhwa.dot.gov/ environment/climate_change/adaptation/ongoing_and_ current_research/gulf_coast_study/gcs.cfm. Lupes reported that the Phase I study used the Inter- governmental Panel on Climate Change, or IPCC, termi- nology for climate assumptions, estimating that a sea level rise of 1 to 6 feet was likely for the area, with an increase of 2 to 4 feet likely by 2100. The Phase 1 study found that a sea level rise of 4 feet could permanently flood almost a quarter of the Interstate miles in the region, 28% of arte- rial road miles, numerous New Orleans transit routes, over 70% of the port facilities, 9% of the freight rail facilities, and three airports in the area. She noted some caveats with the high-level sketch analysis of impacts, which was based on land elevation rather than the height of facilities. The analysis did not recognize if a facility was on piers above a floodplain, for example. It also did not consider protective structures such as sea walls. In addi- tion, a small flooded segment may render a larger portion of the infrastructure inoperable. Lupes reported that the Phase II study focusing on Mobile was conducted from 2009 to 2015. The study identified the key infrastructure in the region for each mode, developed projections of climate change for sea level rise and storm impacts, and examined the sensitiv- ity of roads, bridges, port facilities, and other infrastruc- ture to weather and climate impacts. It also developed a method of identifying critical assets that used a high, medium, or low scale. Criticality was evaluated by applying mode-specific criteria related to socioeconomic importance, use and operational characteristics, and the health and safety role in the community. This informa- tion was used to assess the vulnerability of crucial assets in the region by using an indicator-based approach to vulnerability. She noted that several hundred assets were considered to be highly critical. Because detailed vul- nerability assessments could not be conducted on each asset, the study identified appropriate indicators for the three components of vulnerability: exposure, sensitiv- ity, and adaptive capacity. The indicators suggest how exposed, sensitive, and adaptive each asset is to the pro- jected changes in climate. Lupes described the process of mapping different sea level–rise scenarios to determine the possible exposure of different assets. Based on the results from the indica- tor screening, the study identified a smaller set of key vulnerable facilities for each mode. She noted that more detailed engineering assessments were conducted on some of the assets as part of follow-up studies. Lupes discussed some of the potential implications for transportation planning identified in the study. She noted that climate change is not routinely considered today, but that the longevity of infrastructure argues for its integration. She suggested that the current practice focusing on a 20-year time frame is not well-suited to the assessment of climate impacts. Petkovic described the second case study, which focused on the Languedoc–Roussillon region in France. She noted that the preliminary study began in 2009, and the French National Adaptation Plan was approved in 2011 (www.development-durable.gouv .fr/The-national-climate-change.html). A discussion of the recently published National Climate Change Adaptation Plan: Transportation, Infrastructure, and Systems is available at http://www.sciencedirect .com/science/article/pii/S2352146516300448. The Languedoc–Roussillon region includes 215 kilometers (134 miles) of the Mediterranean coastline between the border of Spain and the Rhône delta. With a popula- tion of approximately 3 million people, Languedoc– Roussillon is primarily an agricultural area. Numerous resorts and historical monuments also make tourism an important part of the economy. The port of Leucate includes petrochemical facilities. She noted that if cur- rent trends continue, the population could increase by 30% by 2070. Petkovic reported that Languedoc–Roussillon was selected as a study site due to the exposure of many low-lying coastal areas to ongoing erosion and persis- tent inundation during storm events. The projected sea level rise adds to concerns in the region. She reviewed the assumptions used in the study. She noted that the conservative estimate of 1 meter (3 feet) of sea level rise by 2100 was used in 2009 due to all the uncertainties surrounding climate change. She suggested these esti- mates would not seem as conservative today given the advances in climate science. Other estimates used in the study included the extreme water level for a 100- year storm at 2 meters (6 feet), resulting in temporary inundation, and an erosion zone of 500 meters (546.8 yards) inland. Similar to the Gulf Coast study, existing protection measures were not taken into account, nor were natural protection barriers. In addition, despite the increasing population in the region, the current popula- tion was used. Petkovic summarized some of the main findings from the Languedoc–Roussillon case study. The permanent inundation from sea level rise by 2100 was estimated to result in the displacement of 80,000 people and the destruction of 140,000 residences. The study also used available insurance data and assumptions of the share of insured and uninsured properties to estimate the costs associated with these losses. It was noted that