Sustainable IT aims to minimize environmental and climate impacts through infrastructure, coding, and operational techniques. Monitoring and measurement systems identify what's working and what isn't. The State of Green Cloud Software Practices outlines four main approaches: Operational efficiency focuses on reducing machines and resources required for applications and processes, which can cut down on carbon usage by up to five to tenfold. Architecting for minimal carbon involves designing software from an energy efficiency standpoint, while energy efficiency aims to reduce the amount of energy required to run applications. Hardware efficiency extends the longevity of hardware to conserve resources and limit device creation. Measuring sustainable IT requires creating key performance indicators (KPIs) based on technical and business metrics, such as proxy metrics for compute, network, and storage resources and business metrics like number of active users, completed transactions, and cost of cloud spend. By tracking these KPIs, organizations can quantify performance over time and reduce their energy usage to align with environmental and social values.