Guardian: Ministers have scrapped radical plans to test a carbon rationing scheme that would have forced citizens to carry a carbon card to swipe every time they bought petrol or paid an electricity bill. The plan was announced by David Miliband, former environment secretary, in 2006 as a way to cut greenhouse gas emissions and tackle global warming. But officials from the Department for Environment, Food and Rural Affairs (Defra) said today that the idea was too expensive and would be …