Cities cover 3 percent of the earth’s land surface yet they create more than 70 percent of all carbon emissions. To keep global temperature increases to 1.5°C or below, cities have to achieve net-zero emissions by mid-century. This report provides a global framework and recommends an integrated energy approach, defined as “systemic efficiency”, as a solution to the current environmental, economic, health, and social crises. Systemic efficiency encompasses clean electrification, smart digital technology, and efficient buildings and infrastructure, along with a circular economy approach to water, waste, and materials. By taking a holistic approach, cities have an opportunity to boost their resilience to withstand a range of potential future climate- and health-related crises.