Some of the most frequently asked questions I have gotten from journalists this week: Why does the encyclical matter? What impact will it have? Why is it getting all this attention?
Let's start with the last question: Why is it getting all this attention?
The encyclical, "Laudato Si',
First, there is a growing consensus around the world that we need to take better care of the environment. Scientific consensus exists that climate change is happening, and human activity is causing it. People are growing in their awareness of environmental problems, but they also see that so far, the world has done little to respond to the crisis.
The second reason the encyclical is getting so much attention is because it is from Pope Francis. The pope is admired, respected, and even loved all over the world by Catholics and non-Catholics alike. Everyone is fascinated by this pope, and he has an ability to communicate in simple language that average people can understand.
It is true that previous popes spoke or wrote about the environment and global warming, but their message rarely got through to the public for two reasons.
First, the media were much more interested in writing stories about popes and condoms than stories about popes and the environment.
Second, in the last two papacies, papal statements tended to read like academic dissertations. The church has never been very good at communicating Catholic social teaching, whether it has been on justice, peace or the environment.
Francis, on the other hand, writes more like a journalist than an academic. Anyone who can read a newspaper can read this encyclical and get something out of it.
In other words, the encyclical is getting so much media attention because it is on the right topic, at the right time, by the right person.
Why does the encyclical matter?
The encyclical matters because it is an authoritative message by one of the world's great religious leaders. The encyclical will stimulate homilies and discussions in parishes around the world. It will become a source of inspiration and ideas for activists, preachers, teachers, theologians and authors who will echo and develop the pope's message.
In his encyclical, the pope begins with looking at the facts: What have we been doing to the earth? He then argues that how we treat the earth, how we respond to climate change, are moral questions -- in fact, some of the most important moral issues of our time.
Those who argue that the pope should stick to faith and morals and not political issues don't seem to think there are any Catholic moral issues outside the bedroom. What can be a more important moral issue than one that could cause the death and displacement of millions of people?
The encyclical is also an invitation to dialogue. The pope does not claim to have all the answers. The more specific his policy recommendations, the less authoritative he becomes. He is inviting economists, business people, public officials, environmentalists, inventors and religious leaders to all come together for a conversation on how to protect the environment. Anyone with a good idea is welcome.
The encyclical also matters because it puts the Catholic church firmly behind the environmental movement. With the pope's embrace, the environmental movement goes mainstream. They can no longer be denigrated as tree-huggers and Gaia worshippers.
Despite its efforts, the environmental movement has had only limited success. Frankly, people are not going to change their lifestyles to protect polar bears. But if history shows us anything, it is that religion can motivate people to do extraordinary things. Religious motives can move people to self-sacrifice, to give up their own self-interest for a greater good. The environmental movement needs believers of every faith who are motivated by their religious convictions to protect God's creation.
What impact will the encyclical have?
The pope is calling the world to a conversion that will have a huge impact on how we live, how our economy works, and how governments operate. "Revolutionary" is almost too weak a word. It will require an extraordinary change in human vision and behavior to accomplish this peaceful revolution. It will require sacrifice from everyone, especially those who are rich and powerful, who are enjoying the fruits of the status quo.
Doing what the pope asks will not be easy, but the pope encourages us to trust in a loving God and a powerful Spirit that can renew the face of the earth. His encyclical is remarkable in that it does not depend primarily on fear to motivate people to care for the earth. Rather, he emphasizes love as the motivating force.
We cannot expect the encyclical to miraculously change human attitudes and behavior overnight. Rather, the encyclical is the beginning of a process that will go on for years. It requires that each of us get involved for the long haul. This is a marathon, not a sprint.
As a social scientist, I am very pessimistic that we can avoid an environmental catastrophe, but as a Christian, I have to have hope. Francis' encyclical strengthens that hope.
[Jesuit Fr. Thomas Reese is a senior analyst for NCR and author of Inside the Vatican: The Politics and Organization of the Catholic Church. His email address is firstname.lastname@example.org. Follow him on Twitter: @ThomasReeseSJ.]