Civil defense or civil protection is an effort to protect the citizens of a state from human-made and natural disasters. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation and recovery. Programs of this sort were initially discussed at least as early as the 1920s and were implemented in some countries during the 1930s as the threat of war and aerial bombardment grew. Civil-defense structures became widespread after authorities recognised the threats posed by nuclear weapons.

Emergency management or disaster management is a science and a system charged with creating the framework within which communities reduce vulnerability to hazards and cope with disasters. Emergency management, despite its name, does not actually focus on the management of emergencies, which can be understood as minor events with limited impacts and are managed through the day-to-day functions of a community. Instead, emergency management focuses on the management of disasters, which are events that produce more impacts than a community can handle on its own. The management of disasters tends to require some combination of activity from individuals and households, organizations, local, and/or higher levels of government. Although many different terminologies exist globally, the activities of emergency management can be generally categorized into preparedness, response, mitigation, and recovery, although other terms such as disaster risk reduction and prevention are also common. The outcome of emergency management is to prevent disasters and where this is not possible, to reduce their harmful impacts.