01 — Itinerary footprint
We compute each journey's CO₂e from four levers: flights (DEFRA 2024 emissions factors, economy class), internal transfers (rail-first; car emissions modelled by vehicle class), accommodation nights (lodge-declared energy mix where available, otherwise IEA country grid average), and tour activities (excursion-specific multipliers from GHG Protocol). The output is per-traveller kgCO₂e; the worksheet is included as a PDF appendix in every itinerary brief.