Agence France-Presse: Greenpeace activists on Thursday climbed down a smokestack they scaled two days ago at a coal-fired power plant in central Poland, saying they would now pitch a protest camp at the site of UN climate talks in nearby Poznan. “The politicians negotiating at Poznan need to get serious about preventing dangerous climate change,” Gavin Edwards, head of Greenpeace’s global climate campaign, said referring to the UN climate conference that lasts until December 12. “That’s why we’re …