The nuclear weaponry age began in New Mexico, United States in 1945 with the atom bomb test. The atomic weapons were used during the war in the pacific of world war II. The nuclear weapons in this present day and time are much more lethal with multiple warheads for several targets. The delivery systems land, air, and sea can literally destroy every major city on earth and that's just between the U.S. and Russia. With nuclear weapons research and development the weaponry will only get more deadly bringing us closer to extinction.
A real global thermonuclear war anywhere on this planet would not only kill billions of people but would alter our biosphere for generations to come. This will affect our food supplies, clean water, and our air in the atmosphere for the worst. The current extreme political climate on the planet could lead to the wrong actions or the order to give an immoral or unlawful military use of thermonuclear weapons. By the time nuclear failsafe goes to defcon 2 (nuclear defensive condition two) the inertia to move to a defcon 1 and the use of nuclear weapons on their targets will make nuclear war reality.
It is extremely hard to envisage a situation where military considerations would dictate the necessity of recourse to nuclear weapons and that could justify their use against combatants, given the biosphere effects. The medical tragedy would be catastrophic with deaths from radiation sickness and the environmental destruction would make parts of the planet uninhabitable for sometime to come. The only way to avoid a global thermonuclear war is to eliminate the class of strategic nuclear weapons on the planet making nuclear weapons more contained to regional tactical dangers with successful international mediation.
