Daily Green: The presidential election of 2008 marks an important turning point in the history of American climate policy. We aren’t debating whether to limit emissions of greenhouse gases that accelerate global warming; both major candidates agree we need to do so. The current debate is about how best to rein in these emissions. Sen. Obama offers bolder long-term goals for reducing greenhouse gas emissions, but Sen. McCain also calls for ambitious targets with specific milestones along the way. …