Disaster is a sudden, extremely unfortunate event that affects many people in a negative manner. Some disasters are a result of the forces of nature, and others result from human actions or errors. Experts can monitor elements of nature and make forecasts about the likelihood of certain disasters occurring. However, it is impossible to predict the exact location, time, and magnitude of most disasters. This article discusses disasters in general. For information about specific disasters, see the list of Related articles. 
Disasters caused by forces of nature include such events as droughts, earthquakes, epidemics (outbreaks of disease), floods, violent storms, and volcanic eruptions. Disasters caused by human behavior include such accidents as airplane crashes, industrial explosions, shipwrecks, and train wrecks. Intentional acts, such as acts of terrorism and war, also may bring about disasters. In some cases, natural forces and human actions combine to cause or worsen a disaster. For example, a person who is careless about putting out a campfire might cause a forest fire or wildfire. A drought may increase the chances of the fire starting or spreading. Global warming is another example of how natural forces and human actions may combine to cause disasters. Scientists predict that global warming, which most scientists believe is influenced by human activity, will lead to more extreme weather. It could increase the frequency of such events as dangerous droughts, floods, and heat waves.
Disasters often result in extensive death, injury, and destruction. They also can have a significant economic effect. For example, a drought or flooding may destroy crops and affect the livelihood of an entire region. Damage from an earthquake or hurricane may leave large numbers of people homeless. And a disaster in an area that depends heavily upon tourism could lead to economic hardship for many workers. Sometimes the impact of a disaster is long-lived. For example, environmental contamination from an industrial accident can last for years and cause long-term health problems. Environmental damage from oil spills can persist for decades.
Governments throughout the world have civil defense programs that provide guidance and assistance in public emergencies. Civil defense agencies work to prepare for, respond to, and recover from disasters. During a disaster, they coordinate the efforts of such emergency workers as firefighters, police officers, public works employees, and medical care providers. Private organizations, such as Doctors Without Borders, the Red Cross, and the Salvation Army, also work to lessen human suffering caused by disasters. They provide victims with medical care, clothing, food, shelter, and counseling. In addition, the United Nations, an international, intergovernmental organization, works to help communities prepare for and recover from natural disasters.
