For weeks, journalists have pestered Opposition leader Bill Shorten about the cost of his climate policies. At the first leaders’ debate Mr Shorten revealed that he wouldn’t be able to give voters a figure, explaining, ‘This issue about “give us one number”, I don’t think that’s possible to do.’  Having rejected ‘numbers’ as a method of calculating the cost of his policy, Mr Shorten has come up with an alternative —the Big Mac.