According to the National Research Council (NRC) and others, infrastructure such as roads and bridges, wastewater systems, and National Aeronautics and Space Administration (NASA) centers are vulnerable to changes in the climate. Changes in precipitation and sea levels, as well as increased intensity and frequency of extreme events, are projected by NRC and others to impact infrastructure in a variety of ways. When the climate changes, infrastructure– typically designed to operate within past climate conditions–may not operate as well or for as long as planned, leading to economic, environmental, and social impacts. For example, the National Oceanic and Atmospheric Administration estimates that, within 15 years, segments of Louisiana State Highway 1– providing the only road access to a port servicing 18 percent of the nation’s oil supply–will be inundated by tides an average of 30 times annually due to relative sea level rise. Flooding of this road effectively closes the port.
Decision makers have not systematically considered climate change in infrastructure planning for various reasons, according to representatives of professional associations and agency officials who work with these decision makers. For example, more immediate priorities–such as managing aging infrastructure–consume time and resources, limiting decision makers’ ability to consider and implement climate adaptation measures. Difficulties in obtaining and using information needed to understand vulnerabilities and inform adaptation decisions pose additional challenges.
Key factors enabled some local decision makers to integrate climate change into infrastructure planning. As illustrated by GAO’s site visits and relevant studies, these factors included (1) having local circumstances such as weather-related crises that spurred action, (2) learning how to use available information, (3) having access to local expertise, and (4) considering climate impacts within existing planning processes. As one example, the Milwaukee Metropolitan Sewerage District managed risks associated with more frequent extreme rainfall events by enhancing its natural systems’ ability to absorb runoff by, for instance, preserving wetlands. This effort simultaneously expanded the sewer system’s capacity while providing other community and environmental benefits. District leaders enabled these changes by prioritizing adaptation, using available locallevel climate projections, and utilizing local experts for assistance.
GAO’s report identifies several emerging federal efforts under way to facilitate more informed adaptation decisions, but these efforts could better support the needs of local infrastructure decision makers in the future, according to studies, local decision makers at the sites GAO visited, and other stakeholders. For example, among its key efforts, the federal government plays a critical role in producing the information needed to facilitate more informed local infrastructure adaptation decisions. However, as noted by NRC studies, this information exists in an uncoordinated confederation of networks and institutions, and the end result of it not being easily accessible is that people may make decisions–or choose not to act–without it. Accordingly, a range of studies and local decision makers GAO interviewed cited the need for the federal government to improve local decision makers’ access to the best available information to use in infrastructure planning.