Civil defence consists of all the non-military actions that can be taken to reduce loss of life and property from enemy action. It embraces defence against all types of attack, including conventional explosive bombs or rockets, nuclear weapons and chemical or biological attacks. But in the missile era, civil defence presents many shortcomings. In the case of nuclear attack, short warning times preclude many civil defence measures (such as getting people into appropriate air-raid shelters) and many important factors are unpredictable. The behaviour of sheltered populations under extreme stress is largely unknown. The fire hazard from nuclear attack is only partly explored: a nuclear burst between an envelope of clouds above and snow below could increase the thermal effect (and resulting fires) by a large factor. There are inherent uncertainties as to when an attack may begin and when it may end, which frustrate civil defence actions. The detection of a fleet of approaching enemy bombers does not preclude the possibility of a simultaneous missile attack, nor that enemy submarines may be lurking offshore, both alternatives conveying threats with short warning times. Similarly, the explosion of a single nuclear weapon cannot be interpreted as the end of the attack for any specific area. More weapons may be in the offing at the very time that the desire to emerge from shelters to fight fires and attempt rescue work is at its peak.
Because, if thermonuclear weapons are ever used in numbers, organized community life as we know it will come to an end in any country involved in the conflict, the idea that civil defence against nuclear weapons can serve any useful purpose, is totally irresponsible in that it further anaesthetises people against the realities of nuclear war and its aftermath.