The Carbon Pollution Reduction Scheme (or CPRS) was a cap-and-trade emissions trading scheme for anthropogenic greenhouse gases proposed by the Rudd government, as part of its climate change policy, which had been due to commence in Australia in 2010. It marked a major change in the energy policy of Australia. The policy began to be formulated in April 2007, when the federal Labor Party was in Opposition and the six Labor-controlled states commissioned an independent review on energy policy, the Garnaut Climate Change Review, which published a number of reports. After Labor won the 2007 federal election and formed government, it published a Green Paper on climate change for discussion and comment. The Federal Treasury then modelled some of the financial and economic impacts of the proposed CPRS scheme.