CANBERRA, Nov. 2 (Xinhua) -- World leaders are unlikely to agree on critical climate change limits in Copenhagen, according to Australian opposition leader Malcolm Turnbull.

    "The fact is the treaty won't be signed in Copenhagen," Turnbull told Macquarie Radio on Monday.

    However, he did say he believed climate change was a serious threat.

    "I believe the world should take effective global action.

    "I believe Australia should be part of it and we have to do so in an effective and economically responsible way.

    "That's why I have proposed a series of amendments to Prime Minister Kevin Rudd's poorly designed emissions trading scheme."

    World leaders will meet in Copenhagen in December to thrash out a new climate deal, which aims to help reduce the planet's carbon pollution.

    The Australian government wants its emissions trading legislation passed before the Copenhagen meeting, but the opposition believes it should be deferred until after the talks.