(Adds religious leader, U.S. criticism)
By Sonya Hepinstall
June 18 (Reuters) - Pope Francis' appeal to save the planet won enthusiastic praise from climate change activists, scientists and religious figures on Thursday as a moral imperative to governments to make 2015 a turning point in efforts to slow global warming.
In the first papal document, or encyclical, dedicated to the environment, Pope Francis demanded swift action to head off what he saw as looming environmental ruin and urged the world's leaders to hear "the cry of the earth and the cry of the poor".
He called for "decisive action, here and now," to stop environmental degradation and global warming, squarely backing scientists who say it is mostly man-made.
Activists and scientists celebrated the intervention as bringing a moral element to the political controversy over climate change, which some conservative politicians and business executives - especially in the United States - doubt has been caused by human activity.
"Climate change is no longer just a scientific issue; it is increasingly a moral and ethical one," said Yolanda Kakabadse, president of the WWF international conservation group.
"It affects the lives, livelihoods and rights of everyone, especially the poor, marginalised and most vulnerable communities."
Christiana Figueres, head of the Bonn-based U.N. Climate Change Secretariat, said the encyclical importantly provided a powerful impetus to governments to agree a strong pact when they meet in Paris from Nov. 30 to Dec. 11.
"This clarion call should guide the world towards a strong and durable universal climate agreement in Paris at the end of this year," Figueres said in a statement.
Global warming is blamed by almost all experts on man-made greenhouse gas emissions for causing more heat waves, downpours and rising sea levels. The Paris summit on climate change aims to secure agrement that a rise in world temperatures will be limited to no more than two degrees Centigrade.
"The Vatican has evaluated the scientific evidence for climate change and decided that the world must act to avoid the devastation of our life supporting ecosystem," said Mark Maslin, professor of climatology at University College London.
"When theological, political and scientific leaders all call for rapid decarbonisation of our global economy it must be time we finally listen and create a binding international climate change agreement.”
Neil Thorns, Director of Advocacy at the British Catholic aid agency CAFOD, said the document was carefully timed for maximum impact ahead of the Paris conference.
"The Pope has deliberately released the encyclical in a year of key UN moments that will affect humanity, and today he says that climate change is real, urgent and it must be tackled."
Religious figures also joined in the praise.
Ecumenical Patriarch Bartholomew, spiritual leader of the world’s 300 million Orthodox Christians and a trailblazer in support for the environment, agreed with the pope's "diagnosis".
"A church that neglects to pray for the natural environment is a church that refuses to offer food and drink to a suffering humanity," he said, writing in Time magazine. "At the same time, a society that ignores the mandate to care for all human beings is a society that mistreats the very creation of God."
The encyclical, a leaked version of which was published on Monday by the Italian weekly L'Espresso, met scepticism even before its publication from some conservatives including several U.S. Republican presidential candidates who doubt climate change is man-made.
At a town hall event in New Hampshire a day after formally announcing his candidacy for the 2016 presidential election, Jeb Bush, who converted to Catholicism 25 years ago, said he would take the pope's words with a grain of salt.
"I hope I'm not going to get castigated for saying this by my priest back home,” Bush said on Tuesday. “But I don't get my economic policy from my bishops or my cardinals or my pope."
On Thursday, R.R. Reno, editor of the conservative U.S. monthly First Things, dismissed the pope's criticism of the modern world as "strikingly anti-scientific, anti-technological and anti-progressive" and said he preferred the more hopeful approaches of his predecessors Pope John Paul and Pope Benedict.
The words of Pope Francis, with his considerable moral authority for the world's 1.2 billion Catholics, put sceptics in an "uncomfortable position", said Matthew Watson, reader in Natural Hazards at the University of Bristol.
"Will it prompt a wholesale change in attitudes and behaviour? By itself I doubt it (we can hope)."
Experts agreed the pope had shifted the debate into a higher gear, however.
“The pope’s message brings moral clarity that the world’s leaders must come together to address this urgent human challenge," said Andrew Steer, president of the U.S.-based World Resources Institute think-tank.
"This message adds to the global drumbeat of support for urgent climate action. Top scientists, economists, business leaders and the pope can’t all be wrong."
(Writing by Sonya Hepinstall; Editing by Tom Heneghan)
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