For many years the Catholic Church has maintained that global warming is a real problem and that people should act accordingly, -as stewards of God's earth. Pope Francis has taken it a step farther but it's not a sudden change in position.
I was raised Catholic but no longer consider myself one. I still have a fascination for the Church's history and how it functions. I also share some of its values. To those that consider it an ultra-conservative organization, that's only partially true. It often isn't, at least not in the US political sense of the word "conservative". It's also a very large organization that exists within many countries and cultures. Though there is only one set of beliefs and teachings, the emphasis placed on those different teachings varies from place to place. For example, many Catholics in the US practice birth control even though the official teaching of the Church is that it's a sin (aside from "Natural Family Planning"). Few US priests (at least in my part of the country) are going to attempt to lecture their congregations on it.
So even though the Pope has put more teeth behind the Church's official stance on global warming, that doesn't mean that Catholic climate change skeptics are going to suddenly tow the party line. It will hopefully mean that the larger organization will make funds available to its churches to make them "greener" but I doubt it. Money tends to flow only in one direction within the Church.