CBC: Stephen Harper has changed his mind, reversed his field and is now going to the UN climate change conference in Copenhagen. He didn’t want to do it. Climate change is becoming the most divisive issue in this country since the fight over energy pricing in the 1970s and ’80s. But he had no choice. The man the prime minister has been counting on to shape a climate change policy that Canada would have to accept is now going to Copenhagen himself on Dec. 9. So when U.S. …