Natural Hazards and Public Health in Urban Areas

Abstract

The world’s cities face natural hazards that expose their large, concentrated populations to health, safety, and well-being risks. The most important of these hazards in the urban context can be grouped into several categories: meteorological and hydrological, including extreme heat, flooding, and drought; environmental, including air pollution and wildfires; and geological, including earthquakes. Multiple natural hazards may affect an urban area simultaneously or in sequence, while any hazard may create a cascading interaction with the urban built environment. This produces the potential for what has been called “connected hazard events.” While earthquakes and extreme heat may lead to the deadliest urban disasters, connected hazard events contribute substantially to the full health burden of urban natural hazards. Thus, human activity—including rapid urbanization, biodiversity loss, and climate change—is increasing the frequency, severity, and complexity of many natural hazard-triggered disasters. Public health risk from natural hazards in urban areas is determined by the type of hazard; the extent and nature of population exposure; population vulnerability factors such as age, health status, housing quality, economic well-being, and social conditions; and the capacity of urban systems to cope, adapt and learn. Populations in cities of all sizes and income categories face natural hazards. Among those at highest risk are urban dwellers in the coastal cities of Asia and Africa, and in the informal settlements of the world’s largest cities. While cities in wealthier countries report greater value of assets damaged in hazard events, those in lower income countries report more lives lost, and more people affected by injury, illness, or displacement. Policy and practice strategies for disaster risk reduction and climate change adaptation can reduce the risks and enhance the capacity of city dwellers. Risk and vulnerability assessments, hazard monitoring and mapping, early warning systems, health preparedness and response, nature-based solutions, and population health surveillance are among the strategies with a growing evidence base. Involving city public health agencies can strengthen their impact. Enhanced collaboration of public health and urban planning; more consistent metrics, monitoring, and research, particularly in the most vulnerable low- and middle-income country cities; and developing a culture of preparedness are opportunities to reduce health risks from natural hazards in urban areas.