Climate change and its impacts threaten the well-being of urban residents in all U.S. regions. Essential infrastructure systems such as water, energy supply, and transportation will increasingly be compromised by interrelated climate change impacts. The nation’s economy, security, and culture all depend on the resilience of urban infrastructure systems.

This finding is from chapter 11 of Climate Change Impacts in the United States: The Third National Climate Assessment.

Process for developing key messages: In developing key messages, the report author team engaged in multiple technical discussions via teleconference. A consensus process was used to determine the final set of key messages, which are supported by extensive evidence documented in two Technical Report Inputs to the National Climate Assessment on urban systems, infrastructure, and vulnerability: 1) Climate Change and Infrastructure, Urban Systems, and Vulnerabilities: Technical Report for the U.S. Department of Energy in Support of the National Climate Assessment f0803451-5a89-474a-974f-99c13fdc725d, and 2) U.S. Cities and Climate Change: Urban, Infrastructure, and Vulnerability Issues .01b45a4a-2021-405d-a65b-2340e9ca9677 Other Technical Input reports (56) on a wide range of topics were also received and reviewed as part of the Federal Register Notice solicitation for public input.

Description of evidence base: Recent studies have reported that population and economic growth have made urban infrastructure more fragile and deficient,01b45a4a-2021-405d-a65b-2340e9ca9677 f0803451-5a89-474a-974f-99c13fdc725d with work projecting increased stresses due to climate change6584482e-b3b2-4cb9-83dd-ec57765a0d08 and increased costs of adaptation plans due to more extensive urban development.4c4641ef-54f0-4db0-a7c4-a461b5c0b01f Additionally, a few publications have assessed the main drivers of vulnerability46df8394-9868-427f-b2d4-6baa15a5d3f4 e25d67fc-3995-4b3b-952f-8135dc743086 a7e5b6c2-f086-46b7-86a3-931c740ea774 and the effects of the amalgamation of climate change stresses with other urban and infrastructure stressors.01b45a4a-2021-405d-a65b-2340e9ca9677

New information and remaining uncertainties: Given that population trends and infrastructure assessments are well established and documented, the largest uncertainties are associated with the rate and extent of potential climate change. Since the last National Climate Assessment,e251f590-177e-4ba6-8ed1-6f68b5e54c8a recent publications have explored the driving factors of vulnerability in urban systems46df8394-9868-427f-b2d4-6baa15a5d3f4 e25d67fc-3995-4b3b-952f-8135dc743086 a7e5b6c2-f086-46b7-86a3-931c740ea774 and the effects of the combined effect of climate change and existing urban stressors.01b45a4a-2021-405d-a65b-2340e9ca9677

Assessment of confidence based on evidence: Given the evidence base and remaining uncertainties, confidence is very high that climate change and its impacts threaten the well-being of urban residents in all regions of the U.S. Given the evidence base and remaining uncertainties, confidence is very high that essential local and regional infrastructure systems such as water, energy supply, and transportation will increasingly be compromised by interrelated climate change impacts.

References :

• Global Climate Change Impacts in the United States (e251f590)
• Heat waves and floods in urban areas: a policy-oriented review of ecosystem services (46df8394)
• Coastal flooding, climate change and environmental justice: identifying obstacles and incentives for adaptation in two metropolitan Boston Massachusetts communities (e25d67fc)
• Social Vulnerability to Climate-Sensitive Hazards in the Southern United States (a7e5b6c2)
• U.S. Cities and Climate Change: Urban, Infrastructure, and Vulnerability Issues, Technical Input Report Series, U.S. National Climate Assessment 2011-0101 (01b45a4a)
• Climate Change and Infrastructure, Urban Systems, and Vulnerabilities. Technical Report to the U.S. Department of Energy in Support of the National Climate Assessment (f0803451)
• Investigating Quality of Urban Life: Theory, Methods, and Empirical Research. Social Indicators Research Series, Volume 45 (6584482e)
• Costs of Sprawl 2000. Transit Cooperative Research Program Report 74 (4c4641ef)