Pope Francis isn't the first religious to call on increased efforts to combat climate change, but his voice is the most important right now from the Catholic hierarchy. Staying true to his pledge of prioritizing the environment, he has readied drafts for an encyclical that is expected to be released by June or July ahead of climate talks in Paris at the end of the year.

An encyclical is integral to teachings by the pope and is written with assistance from a small advisory group. While the contents of an encyclical are kept in secret until its release, Pope Francis as well as his top aides shared bits and pieces about the document, exciting environmentalists who are thrilled that a personality such as Francis is backing their cause.

To many conservatives, this cause they call climate change is just a radical environmental agenda so they aren't very pleased when the highest authority in the Catholic Church has decided to throw his weight behind it.

In 1990, John Paul II called on Catholics to protect the environment as part of their special religious obligation and avoid practices such as unrestricted deforestation, burning fossil fuels and dumping industrial waste. In 2010, Benedict XVI championed the use of solar energy in the Vatican while promoting a stop to ecological devastation.

With environmental issues high up on the list of priorities of his predecessors, it doesn't sound too surprising that Francis would take up the same concerns. However, his decision to focus on environmental issues is his own, asserting that climate change is truly happening and people, in part, are to be blamed.

"I don't know if it (human activity) is the only cause, but mostly, in great part, it is man who has slapped nature in the face," the Pontiff said.

As Pope Francis visited Sri Lanka and the Philippines, a third draft for the encyclical was sent to the Congregation for the Doctrine of the Faith, which is the Vatican guardian on orthodoxy, the pope's own theologian and the office of the Vatican Secretary of State, Cardinal Pietro Parolin.

The pope has received their replies and has plans of spending a week in March to focus on reviewing suggestions sent to him. This should also be enough time to finish the encyclical and have it ready for translation into several languages before being released.

Over the last 20 years, major religious groups have rallied for environmental protection. Among the most prominent supporters of efforts to alleviate climate change is the Orthodox Christians' spiritual leader, Ecumenical Patriarch Bartholomew I of Constantinople.