Australian Broadcasting Corporation: Prime Minister Kevin Rudd has not been able to rule out a petrol price rise under the carbon emissions trading scheme. In a rowdy Question Time, the first half of which was dominated by climate change, Mr Rudd was challenged to confirm if the scheme would raise the cost of petrol. Mr Rudd used a statement from former prime minister John Howard last year, in which Mr Howard said reducing carbon emissions would result in higher petrol and energy prices, to condemn the …