How is a carbon footprint assessed?

Reading 10 min

July 30, 2025

Summary

The process of carrying out a carbon audit is a crucial step for businesses, whether by legal obligation or as part of their environmental commitment. Comprised of five main steps, this process aims to locate and analyze greenhouse gas (GHG) emissions and then reduce them. The steps include defining the scope of the calculation, collecting data on emitting activities, using this data, defining an action plan, and finally communicating this plan.

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Introduction

Carrying out a carbon audit is a legal obligation for some companies, and stems from a desire for environmental commitment for others. The ultimate goal of a carbon audit is to locate and analyze GHG emissions in order to reduce them.

But how do you carry out a corporate carbon audit?

Here are the five main steps involved.

Step 1: Define the scope of the carbon footprint calculation

Geographic scope

This involves determining which buildings, facilities, and equipment the carbon footprint calculation applies to. If the company has multiple entities in multiple countries, it is also necessary to define the boundaries around the countries to be included in the calculation.

Operational scope

During this step, the boundaries around the CO2-emitting activities for which the organization in question is considered responsible are defined. These can include direct emissions, such as energy consumption for machinery, and indirect emissions, such as CO2 emissions from raw material suppliers.

Step 2: Collect data on emitting activities

After defining the scope of the carbon footprint calculation, the carbon expert collects information on all CO2 emission sources. These most often include invoices (for energy and logistics), accounting documents (for company assets such as IT equipment), and employee surveys (commuting emissions).

The complexity of data collection

When collecting data, carbon experts generally face several challenges:

A lack of availability among employees who do not appreciate the value of conducting a carbon audit, hence the need to raise staff awareness,
The time required to identify the people who have the data,
Incomplete Excel files and/or those requiring cleaning,
Essential data that is sometimes not recorded (number of machines recycled, etc.).

As a result, this step is one of the most complex and time-consuming in a carbon audit. To address this, the carbon expert will use several tools to speed up the process:

Standard information collection files, with a predefined structure, reusable from one entity to another, and which employees only need to complete.
Information collection guides to indicate to employees what information is required and in what format.
In the event that data is unavailable, the carbon expert will continue the analysis with a hypothesis validated by the company; this will also be documented in the final report.

The importance of preparing data collection.

Prior to data collection, it is strongly recommended to create a diagram establishing the link between employees and the information to be provided. Generally speaking, the more data collection is prepared in advance and collaboratively, by inviting all data managers, the faster it will be completed.

Step 3: Use the collected data

Since data on emitting activities is expressed in different units (kilograms, liters, kWh, kilometers, etc.), during this step, the carbon expert establishes an emission factor for each data item, allowing the activity to be expressed in tons of CO2 equivalent.

To do this, the carbon expert uses one or more emission factor databases provided by organizations such as ADEME. By adding the tons of CO2 equivalent emitted by each activity, the organization’s overall carbon footprint is calculated.

Step 4: Define the action plan

The carbon footprint is fully in line with a CSR (Corporate Social Responsibility) approach and aims to transform the collected data into concrete actions to reduce greenhouse gas (GHG) emissions.

Once the highest-emitting activities have been identified, the company can define a structured action plan, focusing on three time horizons: short, medium, and long term. This plan must be realistic, measurable, and aligned with national climate objectives.

Carbon footprint: What actions can be implemented to reduce GHGs?

On a small scale:

Reducing business travel (video conferencing, carpooling)
Optimizing building energy consumption (LEDs, insulation, thermal regulation)
Purchasing refurbished IT equipment
Choosing service providers committed to a low-carbon approach

On a large scale:

Transforming industrial processes to integrate lower-carbon technologies
Electrifying or renewing the vehicle fleet
Logistics restructuring (short supply chains, shared deliveries)
Investments in renewable energies

Offsetting and transition plan

Once the reduction levers have been exploited, the organization can use a carbon offsetting strategy for residual emissions. This type of offsetting involves financing certified projects: reforestation, sustainable agriculture, carbon capture, etc.

In France, since January 1, 2023, the Climate & Resilience law requires all affected companies to draw up a transition plan following their Greenhouse Gas Emissions Assessment (BEGES), in accordance with national carbon neutrality objectives.

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Step 5: Communicate your carbon plan

During this crucial step, the organization shares its commitments to climate protection with its internal and external partners: the results of its carbon footprint and its efforts to reduce it (action plan).

By communicating its carbon strategy, the organization ensures honesty, particularly regarding the difference between reducing and offsetting its GHG emissions, otherwise there is a justified risk of accusations of “greenwashing.” This step is all the more important as it unites all stakeholders in the organization’s value chain (suppliers, partners, customers, etc.) around climate protection. Communicating its commitments improves its employer brand image, as candidates are increasingly sensitive to this cause. This is one of the benefits of conducting a carbon audit.

Why conduct a carbon audit?

Conducting a carbon audit is a strategic approach for any organization concerned about its environmental impact. Whether due to regulatory requirements or a desire to take climate action, this greenhouse gas (GHG) emissions assessment offers numerous benefits:

Identify the main sources of emissions within the company (energy, transportation, purchasing, etc.)
Prioritize the most effective reduction actions based on the highest-emitting areas
Reduce long-term costs through greater energy efficiency
Improve brand image among clients, partners, and talent sensitive to climate issues
Meet the expectations of stakeholders, investors, and calls for tenders requiring CSR commitments
Comply with legal obligations, particularly for companies with more than 500 employees in France or those subject to the CSRD in Europe

Carbon assessment also serves as a lever for innovation: it allows for the rethinking of certain production, logistics, or mobility models. Finally, by anticipating future environmental regulations, it helps companies reduce risks and sustain their activity in a world in transition. Thus, carrying out a carbon assessment helps create the foundations for a sustainable and responsible transformation.

Which companies are required to produce a carbon footprint assessment?

In France: the BEGES (Greenhouse Gas Emissions Assessment) and the Transition Plan

In France, producing a greenhouse gas emissions assessment (BEGES) is mandatory for certain organizations, under the French Environmental Code (Article L.229-25), reinforced by the Climate and Resilience Act.

This applies to:

Companies with more than 500 employees (or 250 employees in overseas departments)
Local authorities with more than 50,000 inhabitants
Public institutions with more than 250 employees
The State and its departments

Since January 1, 2023, these entities must also produce a transition plan describing the actions implemented to reduce their emissions, in line with national carbon neutrality objectives. The most affected sectors:

Industry (food, metallurgy, chemicals)
Transportation and logistics
Building and construction
Energy
Large-scale distribution
Digital and telecoms (data centers, etc.)

Even without a requirement, any company can conduct a voluntary carbon audit to structure its CSR strategy, anticipate future obligations, or meet stakeholder expectations.

In Belgium: regional obligations and incentives

In Belgium, there is not yet a general national carbon audit requirement for private companies. However:

The Flemish region requires an energy audit for large companies, which may include an estimate of GHG emissions.
Aid is available in the three regions (Wallonia, Brussels, Flanders) to finance voluntary carbon audits as part of an environmental or energy policy.

Some Belgian companies are also subject to European obligations (such as the CSRD) that indirectly require GHG reporting.

In Europe and the rest of the world

In Europe:

The CSRD (Corporate Sustainability Reporting Directive) is gradually requiring more than 50,000 European companies to provide non-financial reporting, including their greenhouse gas emissions (Scopes 1, 2, and 3).

It concerns:

All large European companies
Listed SMEs, starting in 2027
Subsidiaries of non-European groups with revenues exceeding €150 million in the EU

In the rest of the world:

Canada, the United Kingdom, and Switzerland: several regulations or voluntary standards already require the calculation and publication of carbon emissions, particularly for listed companies.

United States: The SEC is preparing regulations requiring emissions reporting for large listed companies.
Numerous voluntary initiatives: GHG Protocol, ISO 14064, Science-Based Targets, etc.

Geographic Area	Companies Affected	Nature of the Obligation	Details
France	- >500 employees (250 in overseas territories) - Local Authorities >50,000 inhabitants - State and services	Mandatory (BEGES)	Every 4 years (companies) Every 3 years (local authorities) + Transition plan since 2023
Belgium	No unified national obligation Regional obligations for large entities	Partially mandatory / Incentive	Energy audits in Flanders Aid available for voluntary audits
European Union	- Large companies (>250 employees or >€40 million turnover or >€20 million balance sheet) - Listed SMEs from 2027 - Subsidiaries of non-EU groups >€150 million turnover	Mandatory (CSRD)	Phased implementation 2025–2028 GHG reporting Scopes 1, 2, and 3
Canada / UK / Switzerland	Large companies listed or subject to local regulations	Varies according to local legislation	Obligations according to financial markets or national standards
International (voluntary)	Any company wishing to anticipate or structure its climate strategy	Voluntary	Standards used: GHG Protocol, ISO 14064, SBTi, etc.

Carbon Footprint: Methodology

Before beginning a carbon footprint assessment, it is essential to choose an appropriate methodology. This methodological framework ensures the consistency, reliability, and comparability of the results obtained.

What are the main Carbon Footprint methodologies?

Carbon Footprint®: Developed by ADEME, this method is widely used in France. It covers all three scopes (direct emissions, indirect energy-related emissions, and other indirect emissions) and is suitable for all types of organizations.
GHG Protocol: An international standard structured around the same scopes. It is particularly used by companies with an international scope or subject to non-financial requirements (such as CSRD).
ISO 14064-1: An international standard for structuring the quantification and reporting of GHG emissions. It is often used in conjunction with the GHG Protocol to formalize climate commitments.

How to choose the right methodology for a Carbon Footprint?

The choice depends on several factors:

Type of organization (company, local authority, association)
Objectives of the assessment (regulatory requirements, CSR strategy, non-financial reporting)
Scope to be covered (France only or multiple countries)
Desire for international comparability

It is recommended to seek the assistance of a carbon expert to choose the most appropriate method and ensure its proper application. Some digital tools, such as D-Carbonize, integrate these standards and automate part of the calculation, which facilitates the process. A well-chosen methodology allows you to create a reliable, efficient, and recognized carbon assessment.

How can D-Carbonize help you carry out your Carbon Assessment?

D-Carbonize is specialized software designed to simplify and make the entire carbon assessment and climate commitment process more reliable. Whether you are an SME, a large company, or a local authority, this tool supports you every step of the way, from data collection to action plan implementation.

D-Carbonize offers you a complete and intuitive solution:

Easy data collection thanks to smart forms, shared with the right people
Automatic conversion of data into CO₂ emissions thanks to up-to-date emission factor databases (ADEME, GHG Protocol)
Clear and personalized analysis of your results, with visualizations by position, site, or scope
Development of concrete action plans with recommendations tailored to your sector and carbon profile
Monitoring of progress over time to effectively manage your climate strategy

D-Carbonize also provides a network of experts to help you:

Comply with regulatory obligations (BEGES, transition plan)
Structure an ambitious and credible CSR strategy
Communicate your commitments transparently

By centralizing all carbon data in a single interface, D-Carbonize saves you time, reduces errors, and accelerates your low-carbon transition. D-Carbonize helps you combine environmental performance with operational efficiency.