As national governments look to step up climate ambition by 2020, they have an enormous opportunity to draw on the dynamism of local governments, the private sector, and civil society in their countries. These actors, in turn, have a key role to play in mobilizing at the domestic level to create conditions that facilitate higher national ambition. Indeed, many around the world are already doing so. While every country’s circumstances are unique, this report draws from a wide range of experiences to map domestic climate action around the world. By identifying the range of forms domestic level climate action can take, as well as best practices, barriers, and solutions, it seeks to inform and catalyze further ambition in the lead-up to 2020.