The next round of major climate treaty negotiations kicks off today in Copenhagen, Denmark, with more than 100 world leaders slated to attend, including President Barack Obama. Louisville’s former Air Pollution Control District Director Art Williams will also be in attendance, as part of the Sierra Club’s national delegation. Williams says the focus will be not only on reducing greenhouse gas emissions but also on renewable energy. In that regard, he says Kentucky’s economy has much at stake.“The outcomes in Copenhagen and after that will probably make coal additionally more expensive as we price carbon in the energy system to encourage other types of energy use," says Williams.As a Sierra Club delegate, Williams will participate not only in formal United Nations meetings but also so-called “side sessions,” where delegates present ideas and discuss solutions in more informal setting.