C40 cities take action to increase resiliency to climate risk

Cities are at the forefront of experiencing a host of climate impacts, including coastal and inland flooding, heat waves, droughts, and wildfires. As a result, there is a widespread need for municipal agencies to understand and mitigate climate risks to urban infrastructure and services – and the communities they serve – according to a new report released by C40 and a group of leading cities.

The C40 Infrastructure Interdependencies + Climate Risks Report summarizes the efforts of a sample of city governments and other public agencies around the world to understand the cascading impacts of climate change on interconnected infrastructure systems at the urban scale. It highlights how the identification of infrastructure interdependencies and climate impacts can serve as a first step in reducing risks to systems.

This topic is a timely one. The 2017 Global Platform for Disaster Risk Reduction is currently underway in Cancun, Mexico, where hundreds of key stakeholders are gathered to discuss ways to reduce disaster risk and build the resilience of communities and nations.

Modern urban infrastructure systems for the energy, transportation, telecommunications water/wastewater, solid waste, and food sectors are highly interdependent, and highly susceptible to the increasing magnitude and frequency of extreme weather events.

Approaches used by city governments to understand and communicate sectoral interdependencies have ranged from initial engagement or relationship-building with infrastructure owners through traditional educational seminars to more hands-on, interactive workshops in which participants from various sectors have mapped interconnections through discussion and drawings.

To assess and communicate climate risks to interdependent infrastructure systems, city agencies have used geospatial mapping techniques that show the exposure of infrastructure assets to climate hazards. Further, local agencies have also performed qualitative vulnerability assessments in which the sensitivity and adaptive capacity of infrastructure are described. In other instances, quantitative risk assessments which monetize the cost of climate impacts on infrastructure have helped make the case for climate adaptation solutions. In some instances, the identification of specific failure points in interconnected infrastructure systems (e.g., weak links in contiguous shoreline protection infrastructure, or temperature thresholds beyond which damage to infrastructure is more likely) have helped tailor the development of adaptation strategies.

Data-sharing among city agencies and infrastructure organizations (e.g., on climate science, assets characteristics, governance structures, etc.) has been crucial in facilitating strategic planning for climate impacts. City agencies that have undertaken collaborative risk assessments using the above approaches have been successful in developing and prioritizing preliminary adaptation strategies to mitigate the impacts of climate change on interdependent infrastructure systems. From this analysis, a handful of best practices and recommendations for city agencies have been identified in the process of engaging infrastructure organizations and facilitating collective action, conducting preliminary analyses of climate risks to interdependent infrastructure, and developing/implementing tailored adaptation strategies.

This study topic was first conceived by municipal staff members from Toronto and Amsterdam who are leading work in their respective cities to understand climate risks and interdependencies. While numerous local agencies have been able to conduct climate risk assessments of infrastructure over which they have operational control, it is often challenging for agencies to engage external sectors in such efforts. The cities of Melbourne, Johannesburg and Bogota joined this study, providing a broader spectrum of case studies.