A leaked copy of Pope Francis' papal encyclical to be released on Thursday on the environment was published in Italy's L'Espresso yesterday, and in it, the pontiff warns that it's, quote, "urgent and pressing" for the world to tackle climate change by reducing carbon emissions and cutting use of fossil fuels.

"Many of those who have more resources and economic or political power seem focused especially on concealing problems or hiding symptoms, trying only to reduce some negative impacts of climate change. But many symptoms  show that these effects will get even worse if we go ahead with the current models of production and consumption."

Some lawmakers in the U.S. who deny the existence of climate change have criticized Francis' encyclical, with Senator James Inhofe of Oklahoma saying, "The pope ought to stay with his job, and we'll stay with ours," and Catholic former Senator and presidential candidate Rick Santorum advising that Francis leave, quote, "science to the scientists and [focus] on what we're good at, which is theology and morality."