Pope FrancisThis Thursday, in a much anticipated move, Pope Francis will release a Papal encyclical, only his second, on the subject of climate change and its impact on the poor.  It is apparently to be titled “Laudato Si, on the care of our common home.”  It is anticipated, and seemingly confirmed by an early draft leaked to the Italian newspaper L’Espresso, that the encyclical will recognize the link between climate change and human activity – particularly the use of fossil fuels.  It is also anticipated that Pope Francis will call for global action to limit climate change and address its impact.

Pope Francis will hardly be the first Pope to speak out about environmental issues.  Pope Benedict addressed the environment in his 2009 encyclical Charity in Truth.  And Pope John Paul II wrote about the environment and the effects of pollution.  But unlike Benedict or even John Paul, Pope Francis’s popularity approaches rock-star levels in the United States and around the world.  The leak of a draft of the encyclical suggests that Pope Francis intends to take a very strong, and detailed, position on climate change and the importance of environmental stewardship.

This encyclical comes just months before Pope Francis’s first visit to the United States, where he will speak before both Congress and the United Nations.  Given the timing of the release of the encyclical, it seems likely that environmental stewardship and climate change will be primary themes of Pope Francis’s visit.

It is hard to predict what, if any, impact this encyclical will have on the debate over climate change in the United States – but the potential is enormous.  With more than 50 million members, the Roman Catholic Church makes up the largest single religious denomination in the United States.  Roughly a third of the members of the United States House of Representatives, and a quarter of the Senate, are Roman Catholic.  A number of leading names in the race for the Republican presidential nomination are also Roman Catholic, including Jeb Bush, Chris Christie, Rick Santorum, and Marco Rubio.