Agence France-Presse: A top Australian politician said on Tuesday the country should introduce “meaningless” carbon trading if big polluters in the developing world do not agree to reduce emissions. Opposition leader Brendan Nelson said he was committed to introducing emissions trading by 2012, but if big polluters like China and India do not make commitments to reduce emissions it should be deliberately toothless. “Our policy has not changed, and that policy is we would implement an …