The Environmental Technical Manual (ETM) adheres to the traditional ICAO Standards and Recommended Practices (SARPs) framework, where SARPs are supported by guidance material for implementation. SARPs delineate the required actions for States or operators to execute CORSIA, defining the "what" and "when" aspects. In contrast, Volume IV of the ETM provides guidance on the procedural aspects ("how") of implementing CORSIA, offering a comprehensive framework for effective implementation.