Atheism has led to some of the “greatest forms of cruelty and violations of justice” known to mankind, the Pope said yesterday.

He also said that humanity would not be saved by scientific progress or political revolution, but only in the hope offered by Christianity.

“A world which has to create its own justice is a world without hope,” he said in an encyclical released yesterday, the most authoritative statement a Pope can issue to the faithful and the second of his pontificate.

In Spe Salvi (Saved by Hope), Pope Benedict said that atheists argued that “a world marked by so much injustice, innocent suffering and cynicism of power cannot be the work of a good God”. Since there was “no God to create justice”, atheists said, Man himself was called on to establish it on Earth. This protest against God was understandable, the Pope said, but “the claim that humanity can and must do what no God actually does or is able to do is both presumptuous and intrinsically false”.

He added: “It is no accident that this idea has led to the greatest forms of cruelty and violations of justice: rather it is grounded in the intrinsic falsity of the claim. A world which has to create its own justice is a world without hope.”

He said that faith in progress through science was illusory. Scientific advances offered mankind “new possibilities for good”, he said, but science also “opens up appalling possibilities for evil, possibilities that did not formerly exist. We have all witnessed the way in which progress, in the wrong hands, can become and has indeed become a terrifying progress in evil”.

He also said that Christianity itself had ignored Christ’s message that true Christian hope involves salvation for all, focusing instead on individual salvation. “We must do all we can to overcome suffering, but to banish it from the world is not in our power,” the Pope wrote. “Only God is able to do this.”

In the 76-page document, peppered with scholarly and theological references but written in a clear, limpid style, Benedict argued that the modern world was shaped by the French Revolution of 1789 and the Russian Revolution of 1917, the latter inspired by the ideas of Karl Marx.

He praised Marx’s “acute analysis” and “precision” in describing his times. But Marx’s “fundamental error” was that he “showed precisely how to overthrow the existing order but did not say how matters should proceed thereafter”. Marxism, the Pope wrote, had left behind “a trail of appalling destruction” because it failed to realise that Man could not be “merely the product of economic conditions”.

Cardinal Albert Vanhoye, the Vatican biblical scholar who presented the document, said that it was addressed not only to Catholics but also to Protestants, Orthodox Christians and nonChristians. The Pope, who has shown increasing concern over global warming and other green issues, said that “Christian hope” also meant protecting the planet.

“We can free our life and the world from the poisons and contaminations that could destroy the present and the future. We can uncover the sources of Creation and keep them unsullied, and in this way we can make a right use of creation, which comes to us as a gift,” he said.

The Pope said that many people reject faith today, “simply because they do not find the prospect of eternal life attractive. What they desire is not eternal life at all, but this present life, for which faith in eternal life seems something of an impediment. To continue living forever – endlessly – appears more like a curse than a gift”. But he concluded that Eternity was “not an unending succession of days in the calendar” but an encounter with Christ after death which is “like plunging into an ocean of infinite love, a moment in which time, the before and after, no longer exists”.