The issue focused on by many as the single biggest cause of global warming is still one that may not be fully understood. But are more studies needed to address it? How does an image of a chicken cross the desk of a prime minister impact on our climate and how should we treat it?This week the UN environment chief, Ban Ki-moon, called for "more effective action" to combat climate change. And with "current progress" it was expected that he would set out to address the issue in his final