Guardian: Ed Miliband, the energy and climate change secretary, yesterday committed the UK to cut greenhouse gas emissions by 80% by the middle of the century, prompting praise from green groups. But there were warnings his ambitious goal will not be achieved if he presses ahead with a new generation of coal-fired power stations and the expansion of Heathrow. The previous government target of a 60% cut on 1990 levels had now been overtaken by the science, said Miliband, agreeing with the …