Pope Francis arrives in the United States later today. One of the issues he’s expected to discuss during his first U.S. visit will be the environment. The Pope caused a stir in June when he released his Papal encyclical on the environment titled, Laudato Si’ (Praise Be to You). He set up his arguments to combat climate change by asking the questions, “What is the purpose of our life in this world?…What need does the earth have of us?…Unless we struggle with these deeper issues…I do not believe that our concern for ecology will produce significant results.” We’ll talk with Peter Raven, a member of the Pontifical Academy of Sciences. They help advise the Pope on scientific matters. (Photo: Associated Press/Ismael Francisco)