Presented to His Holiness the Pope by an assembly of Presidents of Scientific Academies and other scientists from all over
the world convened by the Pontifical Academy of Sciences
Throughout its history, humankind has been confronted with war, but since 1945 the nature of warfare has changed so profoundly
that the future of the human race, of generations yet unborn, is imperilled. At the same time, mutual contacts and means
of understanding between peoples of the world have been increasing. This is why the yearning for peace is now stronger than
ever. Humankind is confronted today with a threat unprecedented in history, arising from the massive and competitive accumulation
of nuclear weapons. The existing arsenals, if employed in a major war, could result in the immediate deaths of many hundreds
of millions of people, and of untold millions more later through a variety of after-effects. For the first time, it is possible
to cause damage on such a catastrophic scale as to wipe out a large part of civilization and to endanger its very survival.
The large-scale use of such weapons could trigger major and irreversible ecological and genetic changes, whose limits cannot
Science can offer the world no real defense against the consequences of nuclear war. There is no prospect of making defenses
sufficiently effective to protect cities since even a single penetrating nuclear weapon can cause massive destruction. There
is no prospect that the mass of the population could be protected against a major nuclear attack or that devastation of the
cultural, economic and industrial base of society could be prevented. The breakdown of social organization, and the magnitude
of casualties, will be so large that no medical system can be expected to cope with more than a minute fraction of the
There are now some 50,000 nuclear weapons, some of which have yields a thousand times greater than the bomb that destroyed
Hiroshima. The total explosive contant of these weapons is equivalent to a million Hiroshima bombs, which corresponds to a
yield of some three tons of TNT for every person on earth. Yet these stockpiles continue to grow. Moreover, we face the increasing
danger that many additional countries will acquire nuclear weapons or develop
the capability of producing them.
There is today an almost continuous range of explosive power from the smallest battlefield nuclear weapons to the most destructive
megaton warhead. Nuclear weapons are regarded not only as a deterrent, but there are plans for their tactical use and use
in a general war under so-called controlled conditions. The immense and increasing stockpiles of nuclear weapons, and their
broad dispersal in the armed forces, increase the probability of their being used through accident or miscalculation in times
of heightened political or military tension. The risk is very great that any utilization of nuclear weapons, however limited,
would escalate to general nuclear war.
The world situation has deteriorated. Mistrust and suspicion between nations have grown. There is a breakdown of serious dialogue
between the East and West and between North and South. Serious inequities among nations and within nations, shortsighted national
or partisan ambitions, and lust for power are the seeds of conflict which may lead to general and nuclear warfare. The scandal
of poverty, hunger, and degradation is in itself becoming an increasing threat to peace.
There appears to be a growing fatalistic acceptance that war is inevitable and that wars will be fought with nuclear weapons.
In any such war there will be no winners.
Not only the potentialities of nuclear weapons, but also those of chemical, biological and even conventional weapons are increasing
by the steady accumulation of new knowledge. It is therefore to be expected that also the means of non-nuclear war, as horrible
as they already are, will become more destructive if nothing is done to prevent it. Human wisdom, however, remains comparatively
limited, in dramatic contrast with the apparently inexorable growth of the power of destruction. It is the duty of scientists
to help prevent the perversion of their achievements and to stress that the future of mankind depends upon the acceptance
by all nations of moral principles transcending all other considerations.
Recognizing the natural rights of humanity to survive and to live in dignity,
science must be used to assist humankind towards a life of fulfilment and
Considering these overwhelming dangers that confront all of us, it is the duty of every person of good will to face this threat.
All disputes that we are concerned with today, including political, economic, ideological and religious ones, are small compared
to the hazards of nuclear war. It is imperative to reduce distrust and to increase hope and confidence through a succession
of steps to curb the development, production, testing, and deployment of nuclear weapons systems, and to reduce them to substantially
lower levels with the ultimate hope of their complete elimination.
To avoid wars and achieve a meaningful peace, the powers of intelligence are needed, the powers of ethics, morality and conviction.
The catastrophe of nuclear war can and must be prevented. Leaders and governments have a grave responsibility to fulfill in
this regard. But it is humankind as a whole which must act for its survival. This is the greatest moral issue that humanity
has ever faced, and there is no time to be lost.
II. In view of these threats of global nuclear catastrophe, we declare:
--Nuclear weapons are fundamentally different from conventional weapons. They must not be regarded as acceptable instruments
of warfare. Nuclear warfare would be a crime against humanity.
--It is of utmost importance that there be no armed conflict between nuclear powers because of the danger that nuclear weapons
would be used.
--The use of force anywhere as a method of settling international conflicts entails the risk of military confrontation of
--The proliferation of nuclear weapons to additional countries seriously increases the risk of nuclear war and could lead
to nuclear terrorism.
--The current arms race increases the risk of nuclear war. The race must be stopped, the development of new more destructive
weapons must be curbed, and nuclear forces must be reduced, with the ultimate goal of complete nuclear disarmament. The sole
purpose of nuclear weapons, as long as they exist, must be to deter nuclear war.
III. Recognizing that excessive conventional forces that increase mistrust and could lead to confrontation with the risk of
nuclear war, and that all differences and territorial disputes should be resolved by negotiation, arbitration or other peaceful
means, we call upon all nations:
--Never to be the first to use nuclear weapons;
--To abide by the principle that force or the threat of force will not be used against the territorial integrity or political
independence of another state;
--To seek termination of hostilities immediately in the appalling event that nuclear weapons are ever used;
--To renew and increase efforts to reach verifiable agreements curbing the arms race and reducing the numbers of nuclear weapons
and delivery systems. These agreements should be monitored by the most effective technical means. Political
differences or territorial disputes must not be allowed to interfere with this objective;
--To find more effective ways and means to prevent the further proliferation of nuclear weapons. The nuclear powers, and
in particular the superpowers, have a special obligation to set an example in reducing armaments and to create a climate conducive
to non-proliferation. Moreover, all nations have the duty to prevent the diversion of peaceful uses of nuclear energy to
the proliferation of nuclear weapons;
--To take all practical measures that reduce the possiblity of nuclear war by accident, miscalculation or irrational action;
--To continue to observe existing arms limitation agreements while seeking to negotiate broader and more effective ones;
IV. Finally, we appeal:
1. To national leaders, to take the initiative in seeking steps to reduce the risk of nuclear war, looking beyond narrow concerns
for national advantage; and to eschew military conflict as a means of resolving disputes.
2. To scientists, to use their creativity for the betterment of human life and to apply their ingenuity in exploring means
of avoiding nuclear war and developing practical methods of arms control.
3. To religious leaders and other custodians of moral principles, to proclaim forcefully and persistently the grave human
issues at stake so that these are fully understood and appreciated by society.
4. To people everywhere, to reaffirm their faith in the destiny of humankind, to insist that the avoidance of war is a common
responsibility, to combat the belief that nuclear conflict is unavoidable, and to labor unceasingly towards insuring the
future of generations to come.