Pope Francis has issued an encyclical, calling for fossil fuels to be “progressively replaced without delay”.
The pontiff urges the richer world to make changes in lifestyle and energy consumption to avert the unprecedented destruction of the ecosystem.
Environmentalists hope the message will spur on nations ahead of the UN climate conference in Paris in December.
However, parts of the document, leaked earlier this week, have already been criticized by some US conservatives.
The document has been dismissed by two Republican presidential candidates.
The encyclical, named “Laudato Si (Be Praised), On the Care of Our Common Home”, aims to inspire everyone – not just Roman Catholics – to protect the Earth.
Pope Francis writes that: “We have come to see ourselves as her lords and masters, entitled to plunder her at will.
“The violence present in our hearts, wounded by sin, is also reflected in the symptoms of sickness evident in the soil, in the water, in the air and in all forms of life.”
The Pope criticizes what he calls a “collective selfishness”, but says that there is still time to stop the damage, calling for an end to consumerism and greed.
Vatican spokesman Federico Lombardi launched the pontiff’s second encyclical at a news conference on June 18.
The release comes six months before international leaders gather in Paris to try to seal a deal to reduce carbon emissions.
It has been widely welcomed by environmental groups, with WWF president Yolanda Kakabadse saying it “adds a much-needed moral approach” to the debate on climate change.
Greenpeace leader Kumi Naidoo highlighted passages calling for policies that reduce carbon emissions, including by replacing fossil fuels with renewable energy.
But a leak of the document, published by Italy’s L’Espresso magazine on June 16, got a frosty response from skeptical conservatives in America, including two Roman Catholic presidential candidates.
Presidential hopeful Jeb Bush said he did not get his economic policy from his bishops, cardinals or pope.
Meanwhile Rick Santorum questioned whether Pope Francis was credible on the issue of climate science.
However, many academics have welcomed the pontiff’s input.
The UN’s climate change chief Christiana Figueres says the Pope’s message will influence talks in Paris this year on a deal to tackle global warming.
Developing countries are demanding firmer promises of financial help from rich countries so they can adapt to inevitable changes in the climate and get clean energy to avoid contributing to further warming.
Christiana Figueres said their position would be strengthened by Pope Francis’ insistence that this was the clear moral responsibility of the rich.
The encyclical will be welcomed by poor countries in Africa and Latin America.
The big question is how it will play in the USA, where it has already been dismissed by a Republican presidential candidate Jeb Bush, who is a Catholic.
Leading Republicans have warned the UN that they will undo President Barack Obama’s climate policies – so if the encyclical sways any of the conservative Catholics in Congress that could prove significant.