Edited sentence: Peter Christoff, a former director of Greenpeace Australia-Pacific and current direct of Environmental Studies at the University of Melbourne, argues that "almost two decades after the issue became one of global concern, the 'big' debate over climate change is over.Several Op-Ed columnists assert that the term 'climate change denial' should apply to all people and groups in disagreement with the consensus.There are now no credible scientific sceptics challenging the underlying scientific theory, or the broad projections, of climate change