[PARIS] Pope Francis's encyclical on the environment provides a massive mobilising boost for efforts to reach a UN deal on climate change this year, green campaigners said Thursday.
They hailed the 184-page document, "Laudato Si" as a milestone. For many Catholics, they predicted, it could transform climate from a remote environmental problem into a pressing moral issue demanding action.
Its impact could be far-reaching in the effort to conclude a UN accord on curbing greenhouse-gases, due less than six months from now.
"The Pope's message can only help strengthen the momentum toward an agreement in Paris," said Elliot Diringer, executive vice president of the Center for Climate and Energy Solutions (C2ES), a US thinktank. "(He) is injecting a powerful moral voice into a debate usually mired in science, politics and economics.
"He speaks to our collective conscience, and while he's unlikely to win over many skeptics, he's educating countless others about the stakes and the urgency."
Andrew Steer, head of another US thinktank, the World Resources Institute (WRI), pointed to the spiritual authority and mobilising clout of the Catholic church. "It will speak not only to the 5,000 Catholic bishops nor only to the 1.2 billion Catholics worldwide, but to all people of goodwill who are open to the moral context of climate change," he said.
The long-awaited encyclical named climate change as "one of the principal challenges facing humanity in our day." "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," it warned.
It pounded out the message of inequality, saying poor countries that have least to blame for rising seas, worsening drought and flood will feel its impacts worst, and needed the help of rich economies.
Apportioning responsibility for tackling climate change is one of the thorniest and most complex issues in the troubled UN talks.
Rich countries admit they bear historical blame for emitting most of the greenhouse gases behind today's warming. But they argue tomorrow's warming will come from emerging giants like China and India, which are voraciously burning oil, gas and coal.
These countries retort they are still fighting to rise out of poverty and, for now, still need cheap fossil fuels.
Climate specialists, though, say that the fast-falling cost of wind, solar and other cleaner technologies can widely substitute for fossils in poorer countries - provided they get help for implementing the new technology.
Felipe Calderon, a former Mexican president who is chair of the Global Commission on the Economy and Climate, said the pope had taken a knife to the Gordian knot.
"We can boost the kind of economic growth that can reduce poverty while combatting climate change," said Mr Calderon.
"But to achieve this, we must take bold decisions. This is why the papal encyclical is so opportune and welcome, because we all need its guidance as we face the most important challenges of the 21st century."
The pope also called for "highly polluting fuels... to be progressively replaced without delay." The appeal could spur a movement to pull investments out of coal, oil and gas, suggested some observers.
In the past months, dozens of religious organisations have divested from fossils or endorsed the effort, including the World Council of Churches, representing half a billion Christians in 150 countries.
"We hope (the encyclical) will inspire Catholic communities around the world to look at how their own investments might be financing climate change and to commit to disinvesting from fossil fuels as a matter of faith," said Ellie Roberts of a cross-faith Christian charity, Operation Noah.
The talks, under the UN Framework Convention on Climate Change (UNFCCC), aim at limiting global warming to two degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial times.
The negotiations, due to be concluded at a conference in Paris running from November 30 to December 11, are deep in problems.
They range from scrutiny of national carbon-curbing pledges, the mustering of US$100 billion in annual climate finance promised by rich countries and even the legal status of the accord itself.