The proliferation and stockpiling of nuclear weapons by nuclear powers is a threat to the peace and security of those nations which do not possess nuclear weapons. Fear ranges from anxiety over possibilities of nuclear blackmail to dread of an exchange of missiles by any of the nuclear powers.
Even a nuclear exchange detonating a megaton (1 million tonnes of TNT is the equivalent) would cause a global winter so that the southern hemisphere as much as the north would be affected in this regard. In addition, many military targets are located in countries which have no nuclear, and in some cases very little conventional, defences. For these reasons, and the disruption of all trade movements, all nations have a vital stake in maintaining peace.