Mustering all the pageantry the White House has to offer, President Obama welcomed Pope Francis to Washington today. And in his own opening remarks, Francis didn't just dabble in small talk: Climate change, he warned, is an urgent problem that "can no longer be left to a future generation." He praised Obama's focus on the environment and on air pollution but said the world needed to do more because "we are living at a critical moment of history." Francis also said that as a child of an immigrant family, he's honored to be a guest in the US. Obama, for his part, praised Francis for "shaking us out of complacency" and giving people confidence to pursue a world that is more loving, just, and free. After their opening remarks, the two headed inside to the Oval Office for a one-on-one meeting. (More Pope Francis stories.)