CNN: Tackling climate change and its consequences is the challenge of our generation. Principal Voices final debate of 2008 will take place in Chicago on September 29. As the world moves beyond the debate around climate change’s existence to what its effect will be, our Climate Change Principal Voices will gather in Chicago on September 29 to discuss what we can do to protect our environment and our future. Consensus might be growing that the planet is in a perilous state, …