Pope Francis has urged the world to act quickly to prevent "extraordinary" climate change from destroying the planet and says wealthy countries must bear responsibility for creating the problem and for solving it.
In his encyclical, the leader of the world's 1.2 billion Catholics blames human greed for the critical situation "Our Sister, mother Earth" now finds itself in.
"This sister now cries out to us because of the harm we have inflicted on her by our irresponsible use and abuse of the goods with which God has endowed her," he writes.
Arguing that environmental damage is intimately linked to global inequality, he goes on to say that doomsday predictions can no longer be dismissed and that: "The earth, our home, is beginning to look more and more like an immense pile of filth."
Green activists hailed the charismatic Argentinian pontiff's widely-trailed intervention as a potential game-changer in the debate over what causes global warming and how to reverse it.
Environmentalists hope the Pope's message will significantly increase the pressure for binding restrictions on carbon emissions to be agreed at global talks in Paris at the end of this year.
But even before the official publication, climate change sceptics had dismissed the document's argument that the phenomenon is primarily man-made and that humanity can reverse it through lifestyle changes, including an early phasing-out of fossil fuels.
The encyclical references the arguments of the sceptics by acknowledging that volcanic activity, variation in the earth's movements and the solar cycle are factors in climate change.
But it maintains that "most global warming in recent decades is due to the great concentration of greenhouse gases released mainly as a result of human activity".
Despite having reduced Australia renewable energy target and dismissing the viability of wind farm, Environment Minister Greg Hunt said in response to the Pope's warning that Australia was already making a difference in reducing carbon emissions with its Emissions Reduction Fund.
"The government remains firmly committed and on track to meeting our 2020 target of five per cent below 2000 levels, equivalent to a 13 per cent emissions reduction below 2005 levels," a spokesperson told AAP on Thursday.
The encyclical leaves no doubt that Francis believes the world is on a fast-track to disaster after decades of inaction.
"If present trends continue, this century may well witness extraordinary climate change and an unprecedented destruction of ecosystems, with serious consequences for all of us," he writes.
Bemoaning the "remarkable" weakness of political responses to this, Francis accuses the sceptics of cynically ignoring or manipulating the scientific evidence.
"There are too many special interests, and economic interests easily end up trumping the common good and manipulating information so that their own plans will not be affected," he writes.
"We know how unsustainable is the behaviour of those who constantly consume and destroy, while others are not yet able to live in a way worthy of their human dignity," he adds, saying the time has come for parts of the world to accept decreased growth.
The consequences of climate change, he argues, will include a rise in sea levels that will directly threaten the quarter of the world's population that lives near or on coastlines, and will be felt most acutely by developing countries.
One of the strongest themes in the encyclical is that rich countries must accept responsibility for having caused climate change and should "help pay this debt" by cutting their carbon emissions and helping the developing world adopt sustainable forms of energy generation.
Francis says fossil fuel-based technology needs to be "progressively replaced without delay".
Developing countries will need financial help to do this from "countries which have experienced great growth at the cost of the ongoing pollution of the planet" and this pact has to be enshrined in binding accords.
