Multimodal Sea-Rail-Road: Optimizing CO₂ for Freight Journeys

Decarbonizing supply chains has become an imperative, not just environmentally but also strategically and regulatory. Freight transport, a pillar of the global economy, accounts for a significant portion of greenhouse gas emissions. According to the International Energy Agency (IEA), transport contributed 24% of global energy-related CO₂ emissions in 2021, with freight's share constantly increasing. Facing this reality, optimizing transport modes, particularly through sea-rail-road integration, has become an indispensable solution for supply chain directors and CSR managers.

The challenge is no longer if emissions should be reduced, but how to achieve it effectively and measurably. Regulatory pressure, notably with the Corporate Sustainability Reporting Directive (CSRD) in Europe, demands increased transparency from companies regarding their carbon footprint. Adopting a smart multimodal approach, guided by robust calculation standards like ISO 14083 or the GLEC Framework, is no longer an option but a necessity to maintain competitiveness and compliance, without compromising the reliability and profitability of logistics flows.

The Environmental Lever of Multimodal Transport: Key Figures and Mechanisms

Modal choice has a direct and quantifiable impact on CO₂ emissions. Sea transport, especially for long distances, is the least emissive mode per tonne-kilometer. According to the International Maritime Organization (IMO), a modern container ship emits, on average, between 10 and 40 grams of CO₂ per tonne-kilometer, significantly less than road transport, which ranges from 50 to 150 grams of CO₂ per tonne-kilometer for long-haul trucks. Rail freight positions itself as an excellent terrestrial alternative, with average emissions between 10 and 30 grams of CO₂ per tonne-kilometer, largely thanks to network electrification.

Optimization does not lie in banning a mode of transport, but in the intelligent use of each. For a journey between Asia and Europe, sea transport is indispensable for the main leg. It is on the “first and last mile” that shifting from road to rail or inland waterways makes full sense. For example, moving a 40-foot container from Rotterdam to Lyon by rail rather than by road can reduce CO₂ emissions by over 70% for that segment. A freight train can carry the equivalent of 50 trucks, with significantly lower unitary emissions.

Regulations and Calculation: The ISO 14083 / GLEC v3 Framework

Measuring CO₂ emissions in transport is governed by international standards to ensure comparability and reliability. ISO 14083, published in 2023, establishes requirements and guidelines for quantifying and reporting greenhouse gas emissions from freight and passenger transport operations. It aligns closely with the GLEC Framework (Global Logistics Emissions Council), which is the reference methodology for calculating intermodal logistics emissions.

These methodological frameworks require a granular approach, considering numerous factors: the type of transport mode (ship, train, truck), the type of fuel used (heavy fuel oil, diesel, electricity, LNG), the distance traveled, the payload (gross weight of goods), and the occupancy rate. For example, a Euro VI diesel truck will not have the same emission factor as an electric truck or an electric train. The GLEC Framework distinguishes between direct emissions (scope 1 and 2 according to the GHG Protocol) and indirect emissions (scope 3), with the latter being predominant for shippers who do not operate their own fleets. An ISO 14083 compliant calculation provides a solid basis for CSRD reporting, which begins for some large companies as early as 2025 on 2024 data.

Challenges of Multimodal Orchestration

Integrating multiple transport modes to optimize CO₂ is not without its complexities. The main challenge lies in orchestrating the different stages and the multitude of stakeholders. A sea-rail-road journey often involves a freight forwarder, a shipping company, a railway operator, road carriers, and potentially several ports or inland terminals. Each uses its own information systems (EDI, TMS), creating data silos.

The lack of real-time visibility is a major obstacle. Delays, whether due to storms at sea, port strikes, or rail terminal congestion, can lead to unforeseen disruptions and transfers to more emissive transport modes to meet deadlines. The blocking of the Suez Canal in 2021, for example, caused massive diversions, extending maritime journeys by several days and increasing emissions and costs proportionally. Harmonizing ETA (Estimated Time of Arrival) data and anticipating disruptions are essential to maintaining the environmental efficiency of the chain.

Operational Implementation of CO₂ Optimization

Implementing a multimodal strategy for CO₂ reduction requires a structured approach. Here are the key steps:

1. Comprehensive mapping of existing flows: Identify goods flows, volumes (TEU), current routes, and transport modes used. Collect data on distances, tonnages, and fuels to establish an initial basis for emission calculation. For example, a shipper might realize that a significant portion of its European flows is still “all truck” when a rail alternative exists.
2. Calculation of baseline carbon footprint: Use an ISO 14083 / GLEC v3 compliant calculator to quantify current emissions for each journey. This will establish a baseline and identify emission “hotspots.” A precise calculation might show, for instance, 150 kg of CO₂ emitted for a 40' container between the Port of Felixstowe and Manchester by road, versus approximately 40 kg by rail.
3. Analysis of multimodal alternatives: For identified journeys, actively seek options combining sea, rail, and road. Consider accessible inland terminals, rail service frequencies, and available capacities. Evaluate the potential CO₂ delta for each alternative. A simulation might show that shifting a maritime leg to the Port of Southampton followed by a train to London, rather than a truck from Dover, reduces emissions by 60%.
4. Sourcing and contracting with multimodal carriers: Establish partnerships with rail operators, inland waterway carriers, or freight forwarders specializing in multimodal transport. Negotiate Service Level Agreements (SLAs) including CO₂ targets and reporting modalities. Ensure they can provide emissions data compliant with standards.
5. Implementation of orchestration and monitoring tools: Integrate a platform allowing real-time tracking of containers across their different segments, measuring environmental performance, and anticipating disruptions. The ability to connect your AIS/GPS/EDI keys is crucial for end-to-end visibility. Such a system could alert you to a 48-hour ship delay, allowing you to readjust the subsequent rail segment and avoid an emergency road transfer.
6. Reporting and continuous improvement: Generate reports compliant with CSRD/CBAM requirements. Analyze actual emission data against forecasts, identify new optimization opportunities (e.g., freight consolidation, container fill optimization, use of biofuels), and adjust your strategy accordingly. A 5% annual carbon performance improvement is a realistic goal with rigorous monitoring.

Frequently Asked Questions

Q: Isn’t multimodal transport more expensive and slower than direct road transport? A: Not necessarily. While the initial cost of the intermediate rail segment might be slightly higher for an equivalent transit time, the CO₂ benefits are significant. Moreover, for long terrestrial distances (beyond 300 miles), rail often becomes competitive, or even more economical, especially considering rising carbon costs and road tolls. Transit times can be comparable or even improved by avoiding road congestion.

Q: How can I ensure the traceability of emissions across the entire multimodal chain? A: Traceability is ensured by adopting an ISO 14083 / GLEC v3 certified calculator, which incorporates emission factors specific to each transport mode and fuel type. Real-time data integration via APIs or EDI with different providers (ships, trains, trucks) allows for the consolidation of information and documentation of each stage. Certification of your partners can also simplify the audit.

Q: What are the main risks associated with adopting multimodal transport? A: Risks include the complexity of orchestration, potential delays at transshipment points (port hubs, rail-road terminals), the availability of rail or inland waterway capacities, and coordination among multiple actors. Careful planning, the use of advanced orchestration tools, and transparent communication with partners are essential to mitigate these risks.

Q: Is the GLEC Framework still relevant with the publication of ISO 14083? A: Yes, absolutely. ISO 14083 largely draws from the GLEC Framework and solidifies it as an international standard. The GLEC Framework remains a detailed methodology for intermodal emission calculation and is considered fully compatible and aligned with ISO 14083. Using a GLEC-based system means you are already compliant.

Further Reading

• Logistics — Port-to-port orchestration and AI-powered disruption radar
• ISO 14083 CO₂ Calculator — Measure your sea/road/rail/air emissions
• BYOK — Connect your AIS/GPS/EDI data