An eagerly-awaited message from the pope on the environment calls for action to tackle "unprecedented" climate change and destruction of nature, 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.
In it, the pope warns that on current trends the world faces unprecedented climate change and destruction of the ecosystems, with serious consequences for everyone.
He says that humans need to change their unsustainable lifestyles, and calls for action to cut greenhouse gases, develop renewables and clean energy, improve energy efficiency and ensure sustainable management of forests and oceans.
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 pollution and waste 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 most of the global warming is down to greenhouse gases caused mainly by humans through using fossil fuels.
Vatican spokesman, Father Federico Lombardi, said the document was not the final version and that the official encyclical would still be released on Thursday.
It is highly anticipated, with a third of Catholics in England and Wales saying they will make their lifestyle greener if the pontiff makes an official statement on climate change in a poll for Catholic aid agency Cafod ahead of the publication.
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."
Friends Of The Earth's head of campaigns Andrew Pendleton said: "This keenly awaited and crucial intervention from the pope will put further pressure on our political leaders to take faster and bolder action on climate change.
"The pope is right to highlight climate change – unless we tackle this with far greater urgency we will fail in our guardianship of this precious planet."