* Most awaited, controversial papal document in half century
* Fully backs scientists that most climate change man-made
* Market alone can't solve problems of environment, poverty
* Rich nations must discard "throwaway" consumer culture
By Philip Pullella
VATICAN CITY, June 18 (Reuters) - Pope Francis demanded swift action on Thursday to save the planet from environmental ruin, urging world leaders to hear "the cry of the earth and the cry of the poor" and plunging the Catholic Church into political controversy over climate change.
In the first papal document dedicated to the environment, 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.
In the encyclical "Laudato Si (Praise Be), On the Care of Our Common Home", Francis, the first pope from a developing nation, advocated a change of lifestyle in rich countries steeped in a "throwaway" consumer culture and an end to an "obstructionist attitudes" that sometimes put profit before the common good.
He also took on big business, appearing to back "what consumer movements accomplish by boycotting certain products" in order to force companies to respect the environment.
The most controversial papal pronouncement in half a century won broad praise from scientists, the United Nations and climate change activists, as well as U.S. President Barack Obama, who lauded the pope for making the case "clearly, powerfully, and with the full moral authority of his position."
The pope also raised the wrath of conservatives, including several U.S. Republican presidential candidates and leading lawmakers, who have scolded him for delving into science and politics.
Republican Senator Jim Inhofe, chairman of the Senate Environment and Public Works Committee, said in a statement he was concerned the encyclical "will be used by global warming alarmists to advocate for policies that will equate to the largest, most regressive tax increase in our nation's history."
At a news conference to present the encyclical, Cardinal Peter Turkson, a key collaborator on the landmark document, rejected pre-publication criticisms by some U.S. politicians that the pope should steer clear of political issues.
"Just because the pope is not a scientist does not mean he can't consult scientists," he said, adding with a sly smile that journalists write about many things after consulting experts.
Latin America's first pope, who took his name from St. Francis of Assisi, the patron of ecology, said protecting the planet was a moral and ethical "imperative" for believers and non-believers alike that should supersede political and economic interests.
The clarion call to his flock of 1.2 billion members, the most controversial papal document since Pope Paul VI's 1968 encyclical Humanae Vitae upholding the Church's ban on contraception, could spur the world's Catholics to lobby policymakers on ecology issues and climate change.
The Argentine-born pontiff, 78, decried a "myopia of power politics" he said had delayed far-sighted environmental action. "Many of those who possess more resources and economic or political power seem mostly to be concerned with masking the problems or concealing their symptoms," he wrote.
Because Francis has said he wants to influence this year's key U.N. climate summit in Paris, the encyclical further consolidated his role as a global diplomatic player following his mediation bringing Cuba and the United States to the negotiating table last year.
Francis dismissed the argument that "technology will solve all environmental problems (and that) global hunger and poverty will be resolved simply by market growth".
Time was running out to save a planet "beginning to look more and more like an immense pile of filth" and which could see "an unprecedented destruction of ecosystems" this century.
"Once more, we need to reject a magical conception of the market, which would suggest that problems can be solved simply by an increase in the profits of companies or individuals."
Francis also dismissed the effectiveness of carbon credits, saying they seemed to be a "quick and easy solution" but could lead "to a new form of speculation" that maintained excessive consumption and did not allow the "radical change" needed.
"Doomsday predictions can no longer be met with irony or disdain. We may well be leaving to coming generations debris, desolation and filth," he wrote in the nearly 200-page work.
"This system seems to provide a quick and easy solution under the guise of a certain commitment to the environment," he wrote, referring to carbon trading, "but in no way does it allow for the radical change which present circumstances require."
The release and a high-profile roll-out including Professor Hans Joachim Schellnhuber of the Potsdam Institute for Climate Impact Research were timed to precede the pope's speeches on sustainable development in September to the United Nations and the U.S. Congress.
Schellnhuber said "the science is clear: global warming is driven by greenhouse gas emissions."
Francis, saying he was "drawing on the results of the best scientific research available," called climate change "one of the principal challenges facing humanity in our day" and said poor nations will suffer the most.
In several passages in the six-chapter encyclical, Francis confronted head on both climate change doubters and those who say it is not man-made. He said there was a "very solid scientific consensus" that the planet was warming and that people had to "combat this warming or at least the human causes which produce or aggravate it" because greenhouse gases were "released mainly as a result of human activity."
Francis called for policies to "drastically" reduce polluting gases, saying technology based on fossil fuels "needs to be progressively replaced without delay" and sources of renewable energy developed.
In passages certain to upset conservatives, he called for a "legal framework" to defend the environment.
A major theme was the disparity of wealth.
"We fail to see that some are mired in desperate and degrading poverty, with no way out, while others have not the faintest idea of what to do with their possessions, vainly showing off their supposed superiority and leaving behind them so much waste which, if it were the case everywhere, would destroy the planet," Francis said. (Additional reporting by Patricia Zengerle in Washington; Editing by Tom Heneghan and Alan Crosby)
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