Summary

Mitigation activities seek to lessen the impact of a hazard on a community, or eliminate the hazard altogether. Mitigation activities, techniques, and the policies that govern them have evolved over time as human populations learned from and anticipated future crises. Mitigation strategies in the early 1900s relied heavily on structural mitigation in the form of large public works projects, such as dams and sea walls, to control environmental systems and limit human exposure to environmental extremes. Yet these practices encouraged development in high-risk hazard-prone areas. Beginning in the 1950s and peaking in the 1990s, emphasis shifted to the use of non-structural mitigation techniques, including land use regulations and hazard insurance, to steer development away from high-risk landscapes. Policies enacted during this time period and large-scale disasters of the 21st century provide important lessons for mitigation and building resilience to future events. Studies of hurricane damage in the United States led to improved building codes, and underscore the importance of nature-based mitigation strategies. Nature-based solutions, such as ecological engineering, ecological restoration as well as blue and green infrastructure development, harness the environment’s own defenses to protect human populations. For example, after the 2004 Indian Ocean tsunami and earthquake, research showed that strategically placed vegetation could slow and dissipate tsunami waves. The European Commission has also encouraged protecting, restoring, and enhancing environmental features to mitigate against hazards. Moreover, the emergence of the climate change crisis and its ongoing impacts have led environmental scientists, ecologists, and disaster scientists to associate mitigation with emerging concepts such as sustainability, adaptation, and resilience. This association has resulted in the incorporation of mitigation efforts in a variety of planning tools, including sustainability and climate adaptation plans. This shift has produced mitigation strategies that prioritize equity and justice in climate hazard mitigation policy and planning. The future of mitigation will rely on collaboration and cooperation across many allied fields to build sustainable and resilient communities that can adapt and respond to future crises.