Environmental Hazards

An environmental hazard is a threat posed by the natural or built environment to humans and the things that are valued in human society. An environmental hazard becomes a disaster when the threat is realized and causes significant human loss. Death, injury, and psychological harm are judged to be more serious than economic or property loss, and threats to nonhu-man environments and their flora and fauna are considered to be the least severe and are frequently left out of measures of environmental hazard unless they lead to a secondary threat to humans or their property.

Environmental hazards are categorized as either natural or technological, though multiple hazards may be linked to one another. Natural hazards include geologic events, like earthquakes, landslides, and volcanic eruptions; hydrologic events, like floods and drought; meteorological events, such as tornadoes and hurricanes; and biologic events, like wildfires, infestations, and diseases. Technological hazards arise from within human systems and are usually accidental in nature. They include industrial failures that release toxic materials into the environment, structural collapse of buildings and bridges, and transportation disasters like plane crashes and train derailments.

A third category of environmental hazard has been increasingly employed to describe events with the potential for catastrophic impact on the global environment. Sometimes referred to as “context hazards,” these include not only unpredictable occurrences like meteor impacts or the mutation of a virus into a deadly pathogen but also chronic, ordinary events. For example, deforestation and the release of industrial contaminants are increasingly implicated in the complex environmental threats posed by global warming.

The connection between human action and natural disaster was first explored at the University of Chicago during the 1950s by geographer Gilbert F. White, who argued that disasters cannot be understood in isolation from human society. Social scientists [Page 321]using a human ecology framework began to investigate disaster prevention and the mitigation of its consequences. Geographers took up a “hazards-based” approach to disaster, analyzing perceptions of hazards and subsequent behavioral responses. Psychologists compared perceptions of risk for hazards that are involuntary (like breathing air pollution) and voluntary (like smoking cigarettes), while anthropologists noted that perceptions of hazard are substantially influenced by cultural tradition. At the same time, sociologists were preoccupied with collective behavior and the dynamics of social organizations that might influence disaster preparedness and response. Earth scientists continued to focus on the physical causes of disasters. Geologists, meteorologists, and hydrologists were developing better systems of disaster prediction, while civil engineers worked on designing more effective technological defenses.

By the 1970s social scientists challenged the “behavioral paradigm” associated with the hazards-based approach and criticized its emphasis on individual action and its minimization of the power of social and economic forces. The new theoretical paradigm (also known as the critical or political economy view) asserted that environmental hazards are not caused by natural or technological processes but by structural inequalities within and between nations that systematically increase the risk to some social groups while sheltering others from threat.

The term risk refers to the probability that a particular hazard will be realized, combined with the severity of its consequences. For example, the coastal landing of a hurricane presents the same hazard to rich and poor; however, the risk of suffering serious harm as a result of the hurricane is significantly greater for the poor than for the rich because they are more vulnerable to the consequences. Vulnerability is the key variable used to measure susceptibility to the harms associated with environmental hazards and to calculate risk. Less-reliable technological systems (those with frequent system failure) and less-resilient social systems (those with reduced capacity for recovery following disaster) are considered to be most vulnerable. Studies that chart the distribution of risk across demographic groups demonstrate that it is the very old and the very young within the lowest socioeconomic and culturally marginalized groups who are the most vulnerable to disasters' harmful effects. The least vulnerable are those with the greatest access to financial, technological, and informational resources.

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