An eagerly awaited message from the pope on the environment calls for urgent action to protect nature and fight climate change, according to a leaked draft.
The final version papal encyclical, a letter sent to 5,000 Catholic bishops worldwide, which will focus on care for the environment and the relationship between climate change and poverty, is being published in five languages on Thursday.
A leaked draft, which has appeared on the website of Italian news magazine L'Espresso in Italian, lays out the scientific and moral reasons for protecting the environment.
The pontiff has spoken before on the effects of climate change on people and nature, but the encyclical comes ahead of a UN meeting to decide new "sustainable development goals" in September and crucial international talks aimed at securing a new global climate deal in Paris at the end of the year.
Speaking in St Peter's Square, Rome, on Sunday, Pope Francis said the encyclical was "addressed to everyone" - not just the world's 1.2 billion Catholics.
He said he hoped it would spark "renewed attention to situations of environmental degradation and to recovery" leading to "greater responsibility for the common home that God has entrusted to us".
The draft said those in poverty were already suffering the most from air and land pollution and would bear the brunt of rising sea levels and extreme weather conditions, and that there was a responsibility to look after the poor and vulnerable in the face of climate change.
The pope has previously said that climate change is mostly man-made and the draft repeats that scientific studies have shown that rising global temperatures are due mostly to human activity.
Vatican spokesman, Father Federico Lombardi, said the document was not the final version and that the official encyclical would still be released on Thursday.
The Catholic Bishops Conference of England and Wales would not comment on the leaked draft of the encyclical.
A third of Catholics in England and Wales say they will make their lifestyle greener if the pontiff makes an official statement on climate change, ahead of a significant publication from the Vatican on the environment.
A poll ahead of the publication of the encyclical found more than seven out 10 (72%) were concerned that the world's poorest people were being hit by climate change and more than three-quarters (76%) said they felt a moral obligation to help them.
Four-fifths (80%) of those quizzed in the YouGov survey last month for aid agency Cafod said that as Catholics they felt a duty to care for God's creation - the Earth.
But the encyclical is likely to spark controversy in the US, where climate sceptics, including many Catholics, feel the pope's views on the environment clash with their doubts about the issue.
Christians across the spectrum in the UK see climate change and environmental degradation as a key issue facing the world, according to polling by aid agency Tearfund.
A survey of more than 1,500 practising Christians asked them unprompted to identify the main social and political problems the world will have to face over the next 10 years and found they were most likely to say climate change or the environment, with 28% citing those issues.
Catholic aid agency Cafod's head of advocacy Neil Thorns said: "We eagerly await the full encyclical later this week and, based on Pope Francis' frequent expressions of concern for the world's poorest people who suffer most from the ruthless pursuit of wealth which treats God's creation as a possession rather than a gift, we hope he will move people to action."