Reuters: China and the United States have outlined an eye-catching "common vision" to secure an ambitious global climate deal later this year, but experts say a centrepiece pledge by Beijing to establish a nationwide carbon market is no game-changer. In a joint statement made during President Xi Jinping's visit to the United States, China confirmed it would launch national cap-and-trade scheme in 2017, forcing big emitters to buy credits to meet CO2 reduction targets. The world's top two greenhouse gas...