Christian Science Monitor: Can a UN Climate Summit about reducing global carbon emissions be successful if leaders from two of th e largest polluters don't show up? China President Xi Jinping and India Prime Minister Narendra Modi won't be joining heads of state from over 120 countries as they plan for a cleaner energy future at a UN Climate Summit in New York Tuesday. Some are concerned about their absence at the New York climate talks widely regarded as a critical preparatory meeting for achieving a negotiated agreement...