The vast majority of buildings that we will use in the coming decades are already built and account for roughly 39% of the carbon footprint as well as other greenhouse gas (GHG) emissions. We cannot address our climate crisis without tackling improved efficiency and electrification of existing buildings. But how? This session will feature presenters who are advancing codes and policies that will effectively decarbonize existing buildings and bring us the scale we seek. New Buildings Institute will share a new resource, the recently released Existing Buildings Decarbonization Code, to help jurisdictions set clear and approachable pathways to cut carbon emissions through existing building codes. This tool presents language that acts as an overlay to the 2021 International Efficiency Conservation Code (IECC) and details the measures needed for cutting emissions from the current building stock. A speaker from the City and County of Denver will present examples of decarbonization policies at a jurisdictional scale including the use of building performance standards and zero energy policies.