Senator BIRMINGHAM (South Australia) (14:36): Mr President, I have a further supplementary question for Minister Wong. Is it not true that the Treasury modelling of the Gillard government's carbon tax assumes all countries engage in an 80 per cent reduction in emissions against business as usual between 2020 and 2050? Given the minister's personal experience of events like the Copenhagen conference, does the minister agree that this is a most heroic assumption on which to punt Australia's future?