Carbon-aware operation, because the time and the place at which computation runs influences how much energy each algorithm consumes when it executes.

Architectural choices, because the overall shape of the application controls which language, which data structures, and which algorithms are used in each part of the system.

Software efficiency, because language, data structures, and algorithms determine how much computation is required to produce one unit of useful result.

Infrastructure efficiency, because the choice of programming language and the design of the algorithms determine how the underlying servers and physical facilities consume power during the routine operation of the system.