Disaster
A disaster is an event that causes such serious harm to people, buildings, economies, or the environment that the affected community cannot handle it alone. The United Nations Office for Disaster Risk Reduction defines a disaster as "a serious disruption of the functioning of a community or a society at any scale due to hazardous events interacting with conditions of exposure, vulnerability and capacity, leading to one or more of the following: human, material, economic and environmental losses and impacts". Natural disasters like avalanches, floods, earthquakes, and wildfires are caused by natural hazards. Human-made disasters like oil spills, terrorist attacks and power outages are caused by people. It may be difficult to separate natural and human-made disasters because human actions can make natural disasters worse. Climate change also affects how often disasters due to extreme weather hazards happen.
Disasters usually affect people in developing countries more than people in wealthy countries. Over 95% of deaths from disasters happen in low-income countries, and those countries have higher economic losses compared to higher-income countries. For example, the damage from natural disasters is 20 times greater in developing countries than in industrialized countries. This is because low-income countries often do not have well-built buildings or good plans to handle emergencies.
To reduce the damage from disasters, it is important to be prepared and have fit-for-purpose infrastructure. Disaster risk reduction aims to make communities stronger and better prepared to handle disasters. It focuses on actions to reduce risk before a disaster occurs, rather than on response and recovery after the event. DRR and climate change adaptation measures are similar in that they aim to reduce vulnerability of people and places to natural hazards.
When a disaster happens, the response includes actions like warning and evacuating people, rescuing those in danger, and quickly providing food, shelter, and medical care. The goal is to save lives and help people recover as quickly as possible. In some cases, national or international help may be needed to support recovery. This can happen, for example, through the work of humanitarian organizations.
Definitions
The United Nations defines a disaster as "a serious disruption of the functioning of a community or a society at any scale". Disasters result from hazards occurring in areas where people live under exposed or vulnerable conditions. Human factors such as inadequate planning, poor development practices, and lack of preparedness can increase community vulnerability to climate hazards.Disasters are defined as events that have significant adverse effects on people. When a hazard overwhelms the capacity of a community to respond or causes widespread injury or damage, it is classified as a disaster. The international disaster database EM-DAT defines a disaster as “a situation or event that overwhelms local capacity, necessitating a request for external assistance at the national or international level; it is an unforeseen and often sudden event that causes great damage, destruction, and human suffering.”
The effects of a disaster encompass human, material, economic, and environmental losses and effects.
UNDRO defined a disaster in a more qualitative fashion as "an event, concentrated in time and space, in which a community undergoes severe danger and incurs such losses to its members and physical appurtenances that the social structure is disrupted and the fulfilment of all or some of the essential functions of the society is prevented." Like other definitions, this looks beyond the social aspects of the disaster impacts. It also focuses on losses. This raises the need for emergency response as an aspect of the disaster. It does not set out quantitative thresholds or scales for damage, death, or injury.
A study in 1969 defined major disasters as conforming to the following criteria, based on the amount of deaths or damage: at least 100 people dead, at least 100 people injured, or at least $1 million damage. This definition includes indirect losses of life caused after the initial onset of the disaster. These could be the effects of diseases such as cholera or dysentery arising from the disaster. This definition is still commonly used. However, it is limited to the number of deaths, injuries, and damage in money terms.
Types
The scale of a disaster matters. Small-scale disasters only affect local communities but need help beyond the affected community. Large-scale disasters affect wider society and need national or international help.Sendai Framework for Disaster Risk Reduction
- For the purposes of defining the scope of the Sendai Framework for Disaster Risk Reduction, the following concepts are understood as follows:
- * Small-scale disasters refer to events that primarily impact local communities and exceed the capacity of those communities to respond independently, thereby requiring external assistance, although not necessarily at the national or international level.
- * Large-scale disasters are events that affect an entire society or substantial portions of it and demand coordinated responses at the national level and, in many cases, support from the international community.
- * Frequent and infrequent disasters are distinguished by the likelihood of their occurrence and the return period of the hazard involved. While infrequent disasters may cause severe immediate damage, frequent disasters can have compounding effects over time, potentially creating long-term or chronic stress for communities and societies.
- * Slow-onset disasters develop progressively over an extended period rather than occurring abruptly. These disasters are often linked to environmental or biological processes such as drought, desertification, rising sea levels, or the spread of epidemic diseases.
- * Sudden-onset disasters arise rapidly and are typically triggered by unexpected hazardous events. Examples include earthquakes, volcanic eruptions, flash floods, industrial or chemical accidents, failures of critical infrastructure, and transportation-related incidents.
Related to natural hazards
Disasters with links to natural hazards are commonly called natural disasters. However experts have questioned this term for a long time.| Example | Profile |
| Avalanche | The sudden, drastic flow of snow down a slope, occurring when either natural triggers, such as loading from new snow or rain, or artificial triggers, such as explosives or backcountry skiers. |
| Blizzard | A severe snowstorm characterized by very strong winds and low temperatures |
| Earthquake | The shaking of the Earth's crust, caused by underground volcanic forces of breaking and shifting rock beneath the Earth's surface |
| Fire | Fires that originate in uninhabited areas and which pose the risk to spread to inhabited areas |
| Flood | Flash flooding: Small creeks, gullies, dry streambeds, ravines, culverts or even low-lying areas flood quickly |
| Freezing rain | Rain occurring when outside surface temperature is below freezing |
| Heat wave | A prolonged period of excessively hot weather relative to the usual weather pattern of an area and relative to normal temperatures for the season. |
| Landslide | Geological phenomenon which includes a range of ground movement, such as rock falls, deep failure of slopes and shallow debris flows |
| Lightning strike | An electrical discharge caused by lightning, typically during thunderstorms |
| Limnic eruption | The sudden eruption of carbon dioxide from deep lake water |
| Tornado | A violently rotating column of air caused by the convergence of an updraft of warm air and a downdraft of cold air |
| Tropical cyclone | Rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls |
| Tsunami | A series of waves hitting shores strongly, mainly caused by the displacement of a large volume of a body of water, typically an ocean or a large lake, usually caused by earthquakes, volcanic eruptions, underwater explosions, landslides, glacier calvings, meteorite impacts and other disturbances above or below water |
| Volcanic eruption | The release of hot magma, volcanic ash and/or gases from a volcano |
Unrelated to natural hazards
Human-made disasters are serious harmful events caused by human actions and social processes. Technological hazards also fall into this category. That is because they result in human-instigated disasters. Human-made hazards are sometimes called anthropogenic hazards. Examples include criminality, social unrest, crowd crushes, fires, transport accidents, industrial accidents, power outages, oil spills, terrorist attacks, and nuclear explosions/nuclear radiation. Catastrophic climate change, nuclear war, and bioterrorism also fall into this category.Climate change and environmental degradation are sometimes called socio-natural hazards. These are hazards involving a combination of both natural and human factors. All disasters can be regarded as human-made, because of failure to introduce the right emergency management measures.
Famines may be caused locally by drought, flood, fire or pestilence. In modern times there is plenty of food globally. Long-lasting local shortages are generally due to government mismanagement, violent conflict, or an economic system that does not distribute food where needed.
| Disaster | Profile |
| Bioterrorism | The intentional release or dissemination of biological agents as a means of coercion |
| Civil unrest | A disturbance caused by a group of people that may include sit-ins and other forms of obstructions, riots, sabotage and other forms of crime, and which is intended to be a demonstration to the public and the government, but can escalate into general chaos |
| Fire | Even with strict building fire codes, people still perish in fires |
| Hazardous material spills | The escape of solids, liquids, or gases that can harm people, other living organisms, property or the environment, from their intended controlled environment such as a container. |
| Nuclear and radiation accidents | An event involving the significant release of radioactivity to the environment or a reactor core meltdown and which leads to major undesirable consequences to people, the environment, or the facility |
| Power failure | Caused by summer or winter storms, lightning or construction equipment digging in the wrong location |