Hazard

A hazard is a potential source of harm. Substances, events, or circumstances can constitute hazards when their nature would allow them to cause damage to health, life, property, or any other interest of value. The probability of that harm being realized in a specific incident, combined with the magnitude of potential harm, make up its risk. This term is often used synonymously in colloquial speech.

Hazards can be classified in several ways which are not mutually exclusive. They can be classified by causing actor (natural, anthropogenic), by type of mechanism (biological, chemical, or physical hazard) or by effect (for example health and safety hazard, fire hazard, or environmental hazard). A common theme across many forms of hazards in the presence of stored energy that, when released, can cause damage. The stored energy can occur in many forms: chemical, mechanical, thermal hazards and by the populations that may be affected and the severity of the associated risk.

For example, a natural hazard event can lead to a natural disaster with highly harmful impact on a society. Some examples of natural hazard events include floods, droughts, earthquakes, tropical cyclones, lightning strikes,volcanic activity, wildfires.^[1] Technological and anthropogenic hazards include for example explosions, the release of toxic materials, structural collapses, and transportation accidents.

The term climate hazard is used in the context of climate change. These are hazards that stem from climate-related events such as wildfires, floods, droughts, sea level rise.^[2]: 1181 Climate hazards can combine with other hazards and result in compound event losses (see also loss and damage). For example, the climate hazard of heat can combine with the hazard of poor air quality. Or the climate hazard flooding can combine with poor water quality.^[3]: 909