Start by identifying the 3 sources accounting for 70 to 80% of the footprint: in almost every case, purchasing, energy and freight. Start two waves in parallel for these sources: a "quick wins" wave (energy, mobility, the 4-hour rule) visible in 3-6 months, and deeper work on purchasing and supplier engagement, requiring 12 to 18 months to produce quantified results. A plan owned by CSR alone will not last: involve the CFO, procurement and operations from the start.
Read the source article: Reduce your Bilan Carbone®: 4 levers and a 3-year plan