Einstein's last message was a dire warning against nuclear war that's still relevant today. Here's what it said.

Albert Einstein and J. Robert Oppenheimer both feared how nuclear weapons would be used in the future. Corbis/Getty Images

•  Einstein urged Roosevelt to fund uranium research, fearing Germany would develop an atomic bomb.
• After the war, the physicist expressed regret for his role in developing the bomb.
• His final public act was to sign a manifesto warning that H-bombs could destroy humankind.

Shortly before his death in 1955, Nobel Prize winner Albert Einstein signed a manifesto written by philosopher Bertrand Russell.

It was Einstein’s last public act and would come to be named the Russell-Einstein Manifesto.

The document expressed fear that the public didn’t understand the power of newly developed hydrogen bombs, which are even more powerful than atomic ones.

In the manifesto, Russell warned, “that a war with H-bombs might possibly put an end to the human race.”

Though the number has fluctuated over the decades, there are still around 12,500 nuclear weapons in nine countries today, so some of the scientists’ fears communicated in the manifesto continue to be relevant today.

‘The war is won, but the peace is not.’

In the years after the US dropped two atomic bombs on the Japanese cities of Hiroshima and Nagasaki, many of the scientists involved in the Manhattan Project developing the weapons expressed remorse for their work.

They feared how similar bombs would be used in future wars.

Though he was never part of the Manhattan Project, Albert Einstein signed a letter to US President Franklin D. Roosevelt in 1939, urging him to “speed up the experimental work” on uranium for potential use in atomic weapons.

Years later, the German physicist called the letter his “one great mistake.”

A new Netflix docudrama, “Einstein and the Bomb,” uses footage and reenactments of the famous scientist and his shifting view of nuclear weapons.

It quotes his 1945 Nobel Prize address expressing concern over the future use of nuclear weapons, saying, “The war is won, but the peace is not.”

Albert Einstein warned that nuclear weapons could lead to the end of humankind. Central Press/Stringer/Getty Images

By signing Russell’s manifesto, Einstein hoped to warn the public about the dangers of these new weapons as his “final public act,” according to physicist Joseph Rotblat, who resigned from the Manhattan Project over moral objections.

Though this was decades before scientists proposed the theory of nuclear winter, the manifesto predicted the use of several H-bombs would lead to “universal death” by “a slow torture of disease and disintegration.”

Rotblat, Frederic Joliot-Curie, Linus Pauling, and other scientists signed the manifesto, which led to the establishment of the Pugwash Conferences on Science and World Affairs. The organization aims to rid the world of weapons of mass destruction.

In 2013, Rotblat wrote that the manifesto’s statement “Remember your humanity, and forget the rest” was as relevant as the day Russell wrote it.

Here’s a full transcript of The Russell-Einstein Manifesto

9 July 1955

In the tragic situation which confronts humanity, we feel that scientists should assemble in conference to appraise the perils that have arisen as a result of the development of weapons of mass destruction, and to discuss a resolution in the spirit of the appended draft.

We are speaking on this occasion, not as members of this or that nation, continent or creed, but as human beings, members of the species Man, whose continued existence is in doubt. The world is full of conflicts; and, overshadowing all minor conflicts, the titanic struggle between Communism and anti-Communism.

Almost everybody who is politically conscious has strong feelings about one or more of these issues; but we want you, if you can, to set aside such feelings and consider yourselves only as members of a biological species which has had a remarkable history, and whose disappearance none of us can desire.

We shall try to say no single word which should appeal to one group rather than to another. All, equally, are in peril, and, if the peril is understood, there is hope that they may collectively avert it.

We have to learn to think in a new way. We have to learn to ask ourselves, not what steps can be taken to give military victory to whatever group we prefer, for there no longer are such steps; the question we have to ask ourselves is: what steps can be taken to prevent a military contest of which the issue must be disastrous to all parties?

The general public, and even many men in positions of authority, have not realized what would be involved in a war with nuclear bombs. The general public still thinks in terms of the obliteration of cities. It is understood that the new bombs are more powerful than the old, and that, while one A-bomb could obliterate Hiroshima, one H-bomb could obliterate the largest cities, such as London, New York, and Moscow.

No doubt in an H-bomb war great cities would be obliterated. But this is one of the minor disasters that would have to be faced. If everybody in London, New York, and Moscow were exterminated the world might, in the course of a few centuries, recover from the blow. But we now know, especially since the Bikini test, that nuclear bombs can gradually spread destruction over a very much wider area than had been supposed.

It is stated on very good authority that a bomb can now be manufactured which will be 2,500 times as powerful as that which destroyed Hiroshima. Such a bomb, if exploded near the ground or under water, sends radio-active particles into the upper air. They sink gradually and reach the surface of the earth in the form of a deadly dust or rain. It was this dust which infected the Japanese fishermen and their catch of fish.

No one knows how widely such lethal radio-active particles might be diffused, but the best authorities are unanimous in saying that a war with H-bombs might quite possibly put an end to the human race. It is feared that if many H-bombs are used there will be universal death – sudden only for a minority, but for the majority a slow torture of disease and disintegration.

Many warnings have been uttered by eminent men of science and by authorities in military strategy. None of them will say that the worst results are certain. What they do say, is that these results are possible, and no one can be sure that they will not be realized. We have not yet found that the views of experts on this question depend in any degree upon their politics or prejudices. They depend only, so far as our researches have revealed, upon the extent of the particular expert’s knowledge. We have found that the men who know most are the most gloomy.

Here, then, is the problem which we present to you, stark and dreadful, and inescapable: Shall we put an end to the human race: or shall mankind renounce war?1 People will not face this alternative because it is so difficult to abolish war.

The abolition of war will demand distasteful limitations of national sovereignty.2 But what perhaps impedes understanding of the situation more than anything else is that the term “mankind” feels vague and abstract. People scarcely realize in imagination that the danger is to themselves and their children and their grandchildren, and not only to a dimly apprehended humanity. They can scarcely bring themselves to grasp that they, individually, and those whom they love are in imminent danger of perishing agonizingly. And so they hope that perhaps war may be allowed to continue provided modern weapons are prohibited.

This hope is illusory. Whatever agreements not to use H-bombs had been reached in time of peace, they would no longer be considered binding in time of war, and both sides would set to work to manufacture H-bombs as soon as war broke out, for, if one side manufactured the bombs and the other did not, the side that manufactured them would inevitably be victorious.

Although an agreement to renounce nuclear weapons as part of a general reduction of armaments3 would not afford an ultimate solution, it would serve certain important purposes. First: any agreement between East and West is to the good in so far as it tends to diminish tension. Second: the abolition of thermo-nuclear weapons, if each side believed that the other had carried it out sincerely, would lessen the fear of a sudden attack in the style of Pearl Harbour, which at present keeps both sides in a state of nervous apprehension. We should therefore welcome such an agreement, though only as a first step.

Most of us are not neutral in feeling, but, as human beings, we have to remember that, if the issues between East and West are to be decided in any manner that can give any possible satisfaction to anybody, whether Communist or anti-Communist, whether Asian or European or American, whether White or Black, then these issues must not be decided by war. We should wish this to be understood both in the East and in the West.

There lies before us, if we choose, continual progress in happiness, knowledge, and wisdom. Shall we, instead, choose death, because we cannot forget our quarrels? We appeal, as human beings, to human beings: Remember your humanity, and forget the rest. If you can do so, the way lies open to a new Paradise; if you cannot, there lies before you the risk of universal death.

Resolution:

We invite this Congress, and through it the scientists of the world and the general public, to subscribe to the following resolution:

“In view of the fact that in any future world war nuclear weapons will certainly be employed, and that such weapons threaten the continued existence of mankind, we urge the governments of the world to realize, and to acknowledge publicly, that their purpose cannot be furthered by a world war, and we urge them, consequently, to find peaceful means for the settlement of all matters of dispute between them.”

Signatories:

Max Born

Percy W. Bridgman

Albert Einstein

Leopold Infeld

Frederic Joliot-Curie

Herman J. Muller

Linus Pauling

Cecil F. Powell

Joseph Rotblat

Bertrand Russell

Hideki Yukawa