The City of Mercer Island has tracked its own operational GHG emissions since 2011; prior to that year, the City used a different protocol and software package to track emissions. The goal for City government  operations is the same as for the community: to reduce emissions 80% below 2007 levels by 2050.

Beyond reducing its own carbon footprint, and demonstrating new technologies, the City also pursues many other ways of improving sustainability and livability in the community, known as Key Performance Indicators (KPIs). These programs may include green building code updates, encouraging walkable neighborhoods, requiring proper stormwater treatment, banning single-use plastic bags, improving bicycle infrastructure, and other wide-ranging measures that may not have a direct connection with greenhouse gas emissions.