Guardian: The tide of public and expert opinion has been turning inexorably against biofuels in recent months. First news began to leak out about hungry Mexicans protesting about rising corn prices, as more and more of the global harvest was siphoned off for ethanol. Then studies by scientists confirmed that all current biofuels are worse – some by an order of magnitude – in greenhouse emissions terms than conventional mineral petrol and diesel. Now the government’s chief scientist has come …