Telegraph: Radical greens — who long ago picked on flying as the ultimate green sin — may be raising a glass of organic elderberry wine to Eyjafjallajökull, if they can pronounce the Icelandic volcano’s name on so heady a brew. But even if it has realised their dreams by grounding thousands of flights, they would be unwise to celebrate. Let’s leave aside how counter-productive it has been to demonise air travel; most measures to save energy and combat global warming, such as insulating homes, …