InsideClimate: As governments on every level begin to face the multiple threats that climate change pose, policymakers have debated the most effective method to curb greenhouse gas emissions. States and cities have experimented with cap-and-trade programs, regulatory schemes and varying ways to spur renewable energy growth.
Boulder, Colo. embarked on one such climate experiment in 2007, when it became what is believed to be the the first municipality in the country to adopt a climate change tax. The city, home...