Carbon footprint is calculated from cradle to gate in CO2 (kg). Usage of the product is not taken into account. Just like the cost calculation a should and a realistic Carbon footprint is calculated based again on the Value Stream Map. Only interesting are in this case the largest contributors. Solving those by either improving the process or even taking another process technology or material. Changing will need a design change and must be weighted between all other industrial parameters as Time, Cost and manufacturing part quality.