Telegraph: China is the world’s biggest source of carbon emissions, followed by the US, Russia then India Photo: REUTERS Ed Miliband, the new Climate Change and Energy Secretary, said that the current target of 60 per cent was not stringent enough to tackle global warning. He told MPs that the Government would not “row back” on green issues, despite the pressures on the economy of the current downtown. Describing the new target, which is compared with 1990 levels, as “tough but …