Sea Level Rise (SLR) is a problem that all coastal communities have to face. Every community is unique, but we hope we can provide some insight for future research. This project proposes to combine transportation vulnerability assessments with social media analysis and community mapping to understand the potential impacts of sea level rise on transportation and potential adaptive responses. Through the examination of past extreme coastal flooding events in Honolulu, it could provide empirical evaluation for potential sea level rise impacts on transportation. The findings not only have practical significance to the case study area but also have the potential to be generalized to similar coastal regions. The approach and methodology could also be applied to assess coastal hazards impact to transportation in other places.
Sea level rise, as one of the effects of climate change, has become a global, regional, and local issue. According to National Oceanic and Atmospheric Administration (NOAA, n.d), the global sea level has been rising over the past century, approximately 2.6 inches above the 1993 average and it continues to increase at a rate of about one-eighth of an inch per year. In the United States, roughly 40 percent of the population lives in relatively high-population-density coastal areas, where sea level plays a role in flooding, shoreline erosion, and hazards from storms (NOAA, 2018). Sea level rise and more frequent extreme events are expected to critically affect transportation (Becken, 2005). According to the U.S Global Change Research program (2016, p. 841), approximately 60,000 miles of coastal roads in the United States are already exposed to flooding from coastal storms and high waves.
This project combines transportation vulnerability assessments with social media analysis and community mapping to understand the potential impacts of sea level rise on transportation and potential adaptive responses. Social media provides a good overview of people’s concern and attitude towards flooding’s impacts on transportation in general at the global, regional, and state level. Localized transportation vulnerability analysis helps to better understand where and how local communities’ transportation accessibilities to different types of opportunities are being affected by sea level rise related flooding. Finally, community mapping and outreach helps to validate and interpret the results of vulnerability analysis and social media analysis, helps transportation researchers and planners to better understand the local problem and engage the local communities in response to sea level rise. The three approaches complement each other and generate the following key findings:
- At the global level, flight cancels and travel delay are the major impact of flood and king tides on the transportation system.
- At the national scale, coastal states have endured more severe impact of flooding hazards on transportation compared to inland states. In another word, coastal flooding has more severe impacts on people’s travel than other types of flooding.
- At the local level, for City and County of Honolulu, the vulnerability in terms of accessibility reduction is unevenly distributed spatially. The North part of the island near Kahuku, the east part near Hawaii Kai, and the central part near Honolulu Harbor may experience more impacts from tidal flooding than others. These communities also have a low level of accessibility even without coastal flooding.
- Accessibility reduction correlates positively with the percentage of affected road in the TAZ, the total length of affected roads, percentage of residents in educational, health and social services industries, and percentage of white alone population, and negatively related with the percentage of residents in public administration, information, and retail industries. Poverty levels, car ownership, age, minority status, and urban rural settings are not significant.
- Work related trips and grocery shopping trips have been more affected than others.
- Finally, despite the dominant concern for sea level rise impacts on future travel, the local community in general considers the impacts of the sea level rise as manageable if appropriate actions are taken.