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Critical infrastructure systems meet communities' needs for safe drinking water, reliable electricity, and dependable internet access. Climate change poses a threat to these systems in that the increasing frequency and severity of many climate hazards heighten risks of disruption and challenge the assumptions used to design and protect these systems. Understanding these risks can help critical infrastructure owners and operators and other stakeholders allocate resources, make investment decisions, and prepare these systems for future hazards.

The Cybersecurity and Infrastructure Security Agency (CISA) requested a climate change risk assessment for the 55 National Critical Functions (NCFs). The authors examined the current and future risk that eight climate hazards — drought, extreme cold, extreme heat, flooding, sea-level rise, severe storm systems, tropical cyclones and hurricanes, and wildfire — pose to the 55 NCFs on a national scale. This analysis focused on three primary steps: (1) identifying climate hazards that span the variety of climate-related hazards that could degrade or disrupt NCFs across the United States and characterizing how they might change by 2050 and 2100; (2) determining the impact mechanisms by which the climate hazards could disrupt NCFs; and (3) assessing the risk that a climate hazard poses to disrupting an NCF by 2050 and 2100 under two scenarios of future greenhouse gas emissions.

Key Findings

  • We assessed 45 of the 55 NCFs to be at risk of at least minimal disruption on a national scale from climate change by 2050 under a scenario that follows current emissions trends. Minimal disruption indicates that these NCFs are expected to meet routine operational needs across the United States even though operations are experiencing some effects from climate change.
  • Twenty-five of the 55 NCFs are at risk of moderate or greater disruption by 2050 in the current emissions scenario. Moderate disruption indicates that these NCFs are expected to be able to meet routine operational needs only in most of the country. Historical examples of moderate disruption include major disasters, such as Hurricane Katrina.
  • Three NCFs — Provide Information Technology Products and Services, Maintain Supply Chains, and Supply Water — are at risk of major or critical disruption due to climate change by 2100 in the current emissions scenario. If these risks are realized, these NCFs could be disrupted to the point that they cannot meet routine operational needs in most or all of the country.
  • Seven NCFs are not at risk of direct impact from climate change in either 2050 or 2100. These are primarily NCFs related to financial services and network (i.e., internet-based) operations and services.
  • Four of the eight climate hazards — flooding, sea-level rise, tropical cyclones and hurricanes, and wildfire — will have an outsized impact on the NCFs.


  • CISA should consider prioritizing specific NCFs for further assessment, communication, and risk mitigation. NCFs identified as being at greatest risk could undergo more-granular risk assessments at the local and regional levels, including further assessment of the mechanisms by which climate hazards could disrupt these NCFs. Such assessments could help inform communication and outreach materials and enhance risk mitigation.
  • Although an NCF might not be disrupted at the national level, regional disruption of an NCF can create national-level consequences, including significant threats to health and safety, economic loss, and risks to national security. A more complete analysis of the consequences of disruption should be conducted to inform the prioritization of future risk mitigation activities.
  • The science underlying climate projections for 2050 and 2100 will be refined over time as understanding increases about the global climate system and about the dynamics of how climate change affects built and natural systems. At the same time, the provision of these functions could change with technological innovation, investments in adaptation or resilience measures, demographic trends, or other determinants. For these reasons, the authors recommend that these risk assessments be revisited frequently to maintain their utility to policy and planning.

This report is part of the RAND research report series. RAND reports present research findings and objective analysis that address the challenges facing the public and private sectors. All RAND reports undergo rigorous peer review to ensure high standards for research quality and objectivity.

RAND is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.