Pope Francis has issued an unexpectedly strong call for action against climate change, saying the crisis is man-made and must be fixed, and its timing may be almost as important as the message itself.

The Pope's message — unforgiving and far from uplifting — comes as world leaders are to gather in Paris later this year to try to finally hammer out an international accord on climate change, and as U.S. presidential hopefuls are gearing up their bids for the 2016 election. 

In fact, the papal encyclical Laudato Si (Praise Be) seems to be strategically timed in the hope of influencing U.S. environmental policy, says Stephen Scharper, a professor of religion and environment at the University of Toronto. In September, Francis will be the first pope to address a joint meeting of the House and Senate on Capitol Hill.

The Pope has street cred ... [He] is saying we cannot be indifferent to the cry of the poor and the cry of the Earth. -  Stephen Scharper, University of Toronto professor

If that is his intended audience, though, it seems this initial message fell at least partly on deaf ears. 

"I don't get economic policy from my bishops, my cardinals or my pope," said Republican contender for president, and Catholic, Jeb Bush, who has admitted to being a "skeptic" on human culpability in global warming.

"I believe religion ought to be about making us better as people and less about things that get into the political realm."

As for the Pope, his message pulled no punches: "The Earth, our home, is beginning to look more and more like an immense pile of filth," Francis wrote in a 192-page encyclical blaming human activity and the use of fossil fuels for "once beautiful landscapes now covered with rubbish."

He went on to say that wealthy nations hiding behind the "magical conception of the market" owe it to the world's poor to clean up their mess.

Social justice

Whether the papal message will resonate within the clanging world of U.S. politics, of course, remains to be seen.

According to Scharper, "this puts the right wing U.S. agenda in a tight space. This Pope has global efficacy and affection. They will look like scrooges if they come out against their Pope."

Just this week Bush told the Faith and Freedom Coalition's annual conference that religion has been "an organizing part of my architecture, if you will, as a person and certainly as an elected official."

On the other hand, U.S. politics will continue to be dominated by the "belief that the U.S. enjoys special favour from God that ensures its economic might," counters McGill University environment and religion professor David Goodin.

"I do not believe the Pope's words will inspire any second thought at all when it comes to fossil fuel-based economic prosperity."

What the encyclical might do, Goodin suggests, is inspire a new generation of Catholics to take up "creation care" to combat climate change and social justice in the name of their faith.  

"This encyclical is aimed at everyone," Francis said of the encyclical, the highest level teaching document a pope can issue. And that broad audience should probably not be underestimated.

"The Pope connects with people," said Dennis O'Hara, a professor of ecological theology at St. Michael's College at the University of Toronto, who feels the general public is getting to a tipping point when it comes to climate change and they expect politicians to start doing something about it.

vatican encyclical

The Vatican's encyclical letter urges world leaders to unite to address 'one complex crisis which is both social and environmental.' (Vincenzo Pinto/AFP/Getty Images)

For example, "Stephen Harper is giving lip service to becoming carbon neutral," O'Hara says. "He's not doing it because he believes it. That's a shift. [Francis] is not the reason for that shift, but he is a part of it."

Laudato Si is the strongest stance the church has taken on climate change and touches on everything from water quality to genetically modified foods to synthetic agro-toxins that kill fish and birds. The encyclical also takes aim at specific programs such as cap and trade and the use of fossil fuels.

"It has become countercultural to choose a lifestyle whose goals are even partly independent of technology," Francis writes. "I would like to enter a dialogue with all people about our common home."

Plight of the poor

The encyclical also brings up one of the major themes of Francis's papacy — the plight of the poor. 

"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," Francis writes.

An "ecological debt," he says, is owed to those whose resources are being extracted to fuel production and consumption in industrialized nations. He calls on individuals to form social networks to press political leaders for change.

"We are not faced with two separate crises, one environmental and the other social, but rather one complex crisis which is both social and environmental," Francis writes in the encyclical.

Some observers believe the Pope's message may spur action at the UN climate negotiations in Paris in December, where developing countries are demanding firmer promises of financial help from rich countries.

"This Pope has street cred," said Scharper. "It will be harder for nations like Canada to hide behind a veil of economic progress when he is shining a light on rabid consumerism.

"The Pope is saying we cannot be indifferent to the cry of the poor and the cry of the Earth."