National Public Radio: KELLY MCEVERS, HOST: Pope Francis delivered an appeal for social justice in a speech today to some of the world's most powerful people. Presidents, prime ministers and diplomats gathered for the U.N. General Assembly. He covered many subjects, but his focus was the environment and how its degradation affects the poor most of all. NPR's Sylvia Poggioli is traveling with the pope, and she joins us now from New York. Hi, Sylvia. SYLVIA POGGIOLI, BYLINE: Hi, Kelly. MCEVERS: I guess it's not surprising...