Agence France-Presse: The UN's climate chief called for urgency Monday as she opened a new round of global talks amid warnings that Earth-warming carbon dioxide levels were approaching a symbolic threshold never seen in human history. Data from the Mauna Loa Observatory in Hawaii have shown the concentration of CO2 in the atmosphere to be at 399.72 parts per million (ppm), Christiana Figueres told climate negotiators in Bonn. "We are just about to cross the 400 ppm threshold," she said in a prepared speech that stressed...