Business Green: The head of the UN climate change secretariat has today opened the final round of negotiations ahead of the Cancun Summit in late November, urging diplomats gathered in Tianjin, China to identify areas where agreement can be reached in Mexico. Christiana Figueres told the 3,000 delegates gathered in the northern port city that they must use the six-day meeting to quot;accelerate the search for common groundquot; ahead of the Cancun Summit. The UN and all of the key countries taking …