Editor's Summary: Several cities have developed innovative initiatives to combat global warming in the absence of concerted federal regulatory action. One such city is Seattle, Washington. In April 2000, the city directed its municipal utility, Seattle City Light, to achieve zero net greenhouse gas emissions through efficiency, renewable energy, and offsets. In July 2001, City Light became the first U.S. utility to commit to reaching zero net greenhouse gas emissions. Yet this program has not come without its challenges. In this Article, Laura Kosloff and Slayde Hawkins examine City Light's program and the litigation that followed in hopes of providing lessons for other municipalities seeking to address climate change.