The GLEC Framework in logistics: emissions calculation and fleet optimisation

The GLEC Framework (Global Logistics Emissions Council Framework) is the international reference methodology for measuring and reporting greenhouse gas emissions from transport and logistics. It is a common, voluntary language that lets shippers and carriers calculate their emissions with the same method and compare results transparently.

Transport and logistics are responsible for roughly a quarter of global energy-related CO₂ emissions, which makes the sector a pillar of any decarbonisation strategy. On top of that, more and more customers (manufacturers, retailers and global operators) require verifiable emissions data from their logistics providers.

Below we explain what the GLEC Framework is, how emissions are calculated with it and how to use it to optimise your fleets.

What is the GLEC Framework and why is it the sector standard?

The GLEC Framework was developed by Smart Freight Centre (SFC) together with leading companies in the sector, international bodies and environmental consultancies. Its aim is to harmonise emissions calculation across all transport modes: road, maritime, air, rail and inland waterway.

Before GLEC, each company measured with different criteria, which made it impossible to add up or compare results within an international logistics chain. GLEC resolved that fragmentation by defining:

• What data to collect (activity, fuel, distance and load).
• Which emission factors to apply and how.
• How to report results in a traceable and verifiable way.

The current version is the GLEC Framework v3.x (the v3.2 update was published in October 2025), fully aligned with ISO 14083. Thanks to this harmonisation, an international shipper can consolidate data from different carriers and obtain a complete, reliable and comparable inventory of logistics emissions.

How does GLEC relate to the GHG Protocol, ISO 14083 and CountEmissions EU?

The GHG Protocol is the most widely used framework for corporate emissions accounting. Its Scope 3, in categories 4 (upstream transport and distribution) and 9 (downstream), covers the impacts of logistics providers. The GLEC Framework translates those principles into an operational methodology specific to transport, and it was recognised by the GHG Protocol itself as the sector standard for logistics.

In 2023, ISO 14083 officially consolidated this approach, setting the requirements for quantifying and reporting emissions from transport operations. As a result, companies that apply GLEC are naturally aligned with ISO 14083 and with European frameworks such as the EU Taxonomy and the CSRD.

At European level, it is worth following CountEmissions EU, the regulation that will establish a common method for calculating emissions from freight and passenger transport services, built on ISO 14083. The Council and the Parliament reached a provisional agreement in November 2025. It does not impose a general obligation to calculate emissions: its mandatory regime kicks in when emissions data for a service are disclosed to third parties (for example, on labels or in tenders). GLEC, by contrast, remains a voluntary methodology, not a law.

How are emissions calculated under the GLEC Framework?

At the heart of GLEC is a simple but powerful formula:

Emissions = activity data × emission factor

This relationship makes it possible to calculate the emissions of any operation, from a last-mile delivery to a multimodal chain combining truck, ship and train.

Activity data as the basis of the calculation

Activity data reflect the magnitude of the service and are expressed in litres of fuel, kilometres travelled or tonne-kilometres (tkm). For example, moving 20,000 tonnes over 500 km is equivalent to 10 million tonne-kilometres. That figure, multiplied by the corresponding emission factor, gives the associated CO₂ equivalent.

The more accurate the data, the more reliable the result. GLEC distinguishes between measured data (highest accuracy), modelled data (estimates) and default values (standard factors published by SFC or agencies such as the European Environment Agency).

Emission factors: from activity to CO₂e

The emission factor represents the CO₂ equivalent emitted per unit of activity and depends on the type of fuel, vehicle efficiency, load factor or electricity mix. By way of illustration, the direct combustion of one litre of diesel emits in the order of 2.68 kg of CO₂ (the GLEC "well-to-wheel" factors are somewhat higher because they include the fuel production phase).

GLEC provides a complete guide to emission factors by transport mode, updated periodically against international reference databases.

Applying the GLEC Framework by transport mode

Road transport

On the road, GLEC considers the type of vehicle, the Euro category, the fuel and the payload. An urban distribution company with diesel trucks calculates its emissions by multiplying the actual litres of fuel by its emission factor.

Maritime transport

For shipping, the calculation starts from fuel consumption, distance and cargo capacity, and adds correction factors based on the efficiency of the vessel, its speed or the type of cargo. Per tonne-kilometre it tends to be one of the modes with the lowest emissions intensity.

Rail transport

The framework distinguishes between diesel and electric trains. For electric trains, the factor depends on the country's energy mix: in Spain, with a growing renewable share, electric rail is one of the land modes with the lowest footprint per tkm.

Air transport

Air presents the highest emission factors per unit transported. GLEC differentiates between short-, medium- and long-haul flights and adjusts the results according to cargo weight and load factor. Shifting cargo from air to maritime or rail reduces the footprint very significantly.

How to implement the GLEC Framework in your company?

Adopting GLEC does not mean starting from scratch; what matters is to structure the process with a clear, progressive methodology:

1. Define the scope and objectives: which operations to include (domestic, international, own or subcontracted fleet, warehousing, last mile) and for what purpose (compliance, responding to customers or alignment with ISO 14083).
2. Collect the activity data: centralise information from GPS, telematics, ERP or fuel invoicing. Data quality is the main success factor.
3. Select the correct emission factors: use values recognised by GLEC, the GHG Protocol or the European Environment Agency, and update them periodically.
4. Calculate the emissions: apply the base formula systematically by journey or transport type.
5. Verify and report: document the source of the data, keep traceability and generate reports compliant with the GLEC format, ready to integrate into the corporate carbon footprint report.

How to reduce logistics emissions?

Measuring is the first step, but the value of GLEC lies in driving efficiency and emissions reduction. By quantifying which routes, vehicles or modes generate the most emissions, the company can prioritise the levers with the greatest impact:

• Fleet renewal towards more efficient or zero-emission vehicles.
• Alternative fuels such as HVO or biomethane, which can significantly reduce life-cycle emissions compared with conventional diesel.
• Route and load optimisation to cut empty kilometres and improve the load factor.
• Efficient driving, which lowers fuel consumption.
• Intermodality, combining rail or sea with road to reduce the overall footprint of the journey.

You can go deeper into these levers in our guide on how trucks can reduce CO2 emissions and in emerging technologies for transport decarbonisation.

Strategic benefits of the GLEC Framework

Adopting GLEC is not just a technical requirement but a commercial advantage. Logistics companies that demonstrate precision and traceability in their emissions are preferred by the large shippers looking for sustainable partners. Among its benefits:

• Alignment with ISO 14083 and the CSRD.
• Transparency for customers reporting their Scope 3.
• Operational savings from optimising routes and consumption.
• A better ESG position, which makes access to green finance easier.
• An edge in tenders, public or private, where GLEC reports are increasingly required.

How Manglai makes implementing the GLEC Framework easier

Implementing GLEC manually is possible, but it requires a large volume of data and coordination between actors. Tools such as Manglai's GLEC solution automate the whole process, from data collection to the report.

The software connects with logistics management systems, ERPs or fleet sensors, extracts the real activity data and applies the correct emission factors by mode, country and fuel. The result is standardised, verifiable reports compliant with GLEC, ISO 14083 and the GHG Protocol, with modules to simulate scenarios (for example, comparing a diesel fleet with electric vehicles, or a road journey against rail).

The GLEC Framework in logistics: from data to climate leadership

The GLEC Framework represents a paradigm shift: for the first time, the sector has a global methodology that turns climate commitments into verifiable, comparable data that is useful for decision-making. In a market where sustainability is measured in numbers, measuring well means competing better.

To calculate and report the emissions of your transport operations, you can rely on Manglai's service footprint.

Frequently asked questions about the GLEC Framework

What is the relationship between the GLEC Framework and ISO 14083?

GLEC was the methodological basis of ISO 14083; applying the framework aligns the company with the standard naturally.

Is the GLEC Framework mandatory?

No. It is a voluntary methodology. An obligation can come from customer requirements, from the CSRD or, at European level, from CountEmissions EU when emissions data for a service are disclosed.

Who requires GLEC reports?

Manufacturers, retailers and international shippers that report their Scope 3 under the GHG Protocol or the CSRD.

What transport modes does it cover?

Road, maritime, rail, air and inland waterway, as well as warehousing and last mile.

Can it be applied internationally?

Yes. It is designed to harmonise logistics calculations across different countries, ensuring global comparability.