UN Secretary-General Ban Ki-moon has added his voice to the growing calls to fight climate change. His comments come as world delegates battle over details for a deal at the Copenhagen conference.

UN Secretary-General Ban Ki-moon said, "Copenhagen can and must be the turning point in the world's efforts to prevent runaway climate change and usher in a new era of green growth for all."

Speaking at the UN headquarters in New York on Tuesday, Ban said there is unprecedented momentum for a deal on climate change, adding that he is optimistic a robust agreement would be reached in the next two weeks. He also believes the agreement will be put into effect immediately after it is agreed upon.