Determine the transport chain legs (e.g., truck to port, ocean vessel, drayage at destination) and assign each leg a transport mode and vehicle/vessel category
Collect distance for each leg using verified route distances (not great-circle) and the cargo's share of total vehicle capacity (load factor or weight fraction)
Apply GLEC Framework default emission intensity values (gCO2e per tonne-km) for each mode and vehicle category from the GLEC Framework reference document
Multiply intensity × distance × cargo weight to obtain leg-level CO2e emissions and sum across all legs for the total shipment footprint
Document the data quality tier (measured, modeled, or default) for each input per the GLEC Framework reporting requirements
Known gotchas
GLEC Framework emission intensities include Well-to-Wheel (WTW) scope; mixing Tank-to-Wheel (TTW) and WTW values in the same calculation produces non-comparable results
Ocean vessel emission intensity varies significantly by vessel size and type; using a generic average instead of the vessel class value can introduce 30–50% error
The GLEC Framework is periodically updated (the 2023 version introduced new vessel categories); confirm which version your calculation uses for consistency with partners
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp