Pope Francis takes on those in the way of action on climate change
Kevin Rafferty says a radical papal letter calling for the protection of "our common home" has already been ruffling feathers in some quarters - even before its official release
Jorge Mario Bergoglio looked an unlikely candidate for mover and shaker of the world, even as he was elected to succeed Benedict XVI as pope in 2013. In his mid-70s, with only one lung, and hailing from Argentina, far from the global power centres, he seemed set for a short, probably irrelevant, papacy.
Yet on Thursday this fragile pope will take the global stage with a prophetic call to all human beings to save the planet from destruction by greed, plunder and thoughtlessness.
Bergoglio took the papal name Francis, after the 12th-century silk merchant's son, who gave up his riches to be a mendicant friar, who talked to the birds, lived among the poor and went to Egypt to try to mediate an end to the fighting in the middle of the Crusades.
Francis was a saint for the earth and its integrity, a patron for the poor, and a saint who preached peace.
Pope Francis' challenge to the world comes in his encyclical letter Laudato Si ("Praised Be"), to be issued on Thursday. Its subtext is "on the care of our common home".
The opening words refer to a canticle of Saint Francis praising God for creation and the richness of the earth. "If the current trend continues, this century could see unheard of climate change and an unprecedented destruction of ecosystems, with grave consequences for all of us," Francis writes, according to a leaked version of the letter, which the Vatican says is an early draft.
The opposition is already blowing up a steam of fury. Leading Republicans in the US, including Catholic presidential hopeful Rick Santorum, are telling the pope to butt out of matters that are not his concern.
Jeb Bush, a Catholic convert, praised the "really cool" pope's openness, but declared that he did not take his economics or climate science from the pope.
Pope Francis' message is far more radical than merely demanding curbs in the burning of fossil fuels: he is calling for a revolution in economics and policy, in the hearts and minds of people, particularly in the rich countries of the world.
The theme will not come as a surprise to anyone who has followed the pope. Last year, he criticised "an economic system centred on the god of money" because it "needs to plunder nature to sustain the frenetic rhythm of consumption that is inherent to it".
He asked: "Isn't humanity committing suicide with this indiscriminate and tyrannical use of nature?"
Will the pope's pontificating have any impact? Long ago, Soviet leader Joseph Stalin mocked the pope because he had no troops with which to enforce his will. These days, the pope has fewer and fewer people going to mass in his churches.
For millions of modern Catholics, the Christian story is a pretty fairytale. Others have turned their backs on the church, horrified by the hundreds of priests who have abused their office by sexual misconduct with children. Republican America professes the faith, until the pope says something uncomfortable.
This time, the pope is appealing beyond Catholics to all human beings to save the earth. The encyclical is a first step. In September, he will address the United Nations and then go to Washington to meet President Barack Obama and address the US Congress, another papal first.
At his meetings with world leaders, Francis will be backed with the scientific support of high-powered members of the Pontifical Academy for Sciences, not all of them Catholics.
Even with God and goodness on his side, Francis has an uphill struggle to get through to leaders whose shortsighted thought is preserving their political skin at the next election. Let us pray for Francis and for the earth.
Kevin Rafferty was editor of The Universe, the best-selling English Catholic newspaper