Carbon footprint calculation is a multidimensional process guided by various guidelines and standards. The calculation involves considering different boundaries, extensive data, and result verification. What factors affect the formation of a carbon footprint?
Calculating the carbon footprint is an important step towards more climate-friendly practices. Instead of fearing errors, the most important thing is to get started. There are many things to consider in emissions calculation, but international guidelines and standards help in moving forward.
The key frameworks for life cycle assessment and carbon footprint assessment are determined by international environmental standards, namely ISO standards, which aim to create consistent rules for global markets. Carbon footprint assessment is guided by the ISO 14000 series of standards, which focus on environmental management and improving the level of environmental protection.
There are also more specific guidelines for carbon footprint assessment at the EU level. The Product Environmental Footprint (PEF) method developed by the European Commission guides the assessment of the environmental impacts throughout a product’s life cycle. It provides guidance on modeling the environmental impacts of a product. The product’s environmental footprint consists of sixteen environmental impact categories. The PEF guidelines define impact assessment models for each environmental impact category and specify the required input data for different product groups.
This guide explains how to calculate a carbon footprint based on these guidelines and what factors affect emissions.
- Fossil, biogenic, and land-use emissions
- Boundaries and life cycle stages
- Primary data and secondary data
- Company-specific assessments (Scopes)
- Product-specific assessments
We need to get rid of fossil emissions. Regardless of whether the calculation is done perfectly, calculating the carbon footprint is always better than no calculation at all. If we are afraid of making calculation mistakes, and do not calculate anything, any amount of emissions can be released into the atmosphere.
1. What must be taken into account when calculating the carbon footprint?
Carbon footprint calculation is based on two variables: activity and emission factor:
Activity variable = any activity that generates emissions
The value of the activity can be stated, for example, in kilograms, tonne-kilometres or kilowatt-hours.
Emission factor = activity intensity
The amount of greenhouse gas emissions is expressed in carbon dioxide equivalents, i.e. as a total measure of emissions, which can be used to add up the effects of different greenhouse gases.
The emission factors are formed mathematically with the help of various studies, articles and reports. The expert goes through the literature and models the emission factors of the products, i.e. calculates how much emissions are generated. In addition to modeling by experts, general databases with different emission factors can also be used in the calculation.
Modeling produces emission factors
Various methods are used for emissions modeling. For example, the International Panel on Climate Change (IPCC) has a collection of formulas that can be used for modeling.
However, there are many other modeling methods, and the results obtained with different methods may vary to some extent. Therefore, comparing the results can be difficult. Calculation methods are often considered confidential information and not publicly disclosed. However, transparency in methods would be important to enable comparison of calculations.
In Finland, there are ongoing efforts to harmonize calculation methods. The LCAFoodPrint project led by the Natural Resources Institute Finland aims to find nationally and even internationally consistent guidelines for emissions modeling.
Emission types: Fossil, Biogenic, and Land Use Impacts
Carbon footprint is influenced by both fossil and biogenic emissions, and emissions resulting from land use and it’s changes.
Fossil emissions are generated from the use of fossil fuels. Fossil fuels such as oil, natural gas, and coal are derived from ancient organic matter that has transformed into fossils deep within the Earth’s crust over millions of years.
These emissions refer to emissions from biobased products primarily derived from forests and agricultural lands. They arise from changes in biogenic carbon stocks, where carbon transitions between the stock and the atmosphere and vice versa. Biogenic carbon is released into the atmosphere, for example, through biomass burning or natural decomposition.
Land use–related emissions
Emissions resulting from land use are greenhouse gas emissions resulting from human activities and land-use changes, such as deforestation, conversion of land for agriculture, urban planning, mining, and urbanization. These emissions are directly or indirectly caused by changes in land and ecosystems. Often, carbon footprint refers only to fossil emissions, and for instance, in company-specific scope calculations and product-specific assessments, it specifically calculates fossil emissions.
The roles of different emissions in carbon cycling and calculations
Fossil emissions are central because they always increase the concentration of greenhouse gases in the atmosphere, thus warming the climate. Therefore, it is important to completely eliminate the use of fossil inputs.
The change in carbon stocks with fossil materials is straightforward. Through combustion, fossil carbon transitions from the stock to the atmosphere and does not return to a fossil stock. With renewable biomaterials, the situation is more complex because carbon that has transitioned from biomass to the atmosphere can be reabsorbed into the biogenic carbon stock during regrowth.
Biogenic emissions are often calculated as zero because the cycle of carbon storage and release for biogenic carbon is significantly shorter than that of fossil carbon. It is currently being discussed whether long-term sequestered carbon and emissions resulting from land use should be taken into account. Presently, these figures should be reported alongside fossil emissions.
System boundaries and life cycle stages
The general rule in life cycle emissions calculation is to account for emissions throughout the entire life cycle, known as the cradle-to-grave boundary. This boundary includes all emissions from the manufacturing of raw materials to the emissions resulting from product disposal.
Another common boundary is to consider emissions only from the manufacturing of raw materials to the point of production. This boundary is often used, for example, in food carbon footprint calculations and is referred to as the cradle-to-gate boundary. In practice, this boundary includes everything that a food company can influence, such as raw material production, transportation to the factory, processing at the factory, and packaging.
Based on these boundaries, life cycle emissions calculation includes various life cycle stages, which include:
- Raw materials
- Product use
- Waste management
Standards define the life cycle stages, although different names may sometimes be used. For example, procurement may also be referred to as transportation. However, the specific terminology does not affect the calculation result. The names of life cycle stages are being harmonized for clarity purposes.
What do the emissions of the different life cycle stages consist of?
Primary data and Secondary data complement each other
In carbon footprint calculations, primary data refers to actual information about activities and impacts, such as the quantity of raw materials or energy consumption. It is raw data obtained directly from suppliers of raw materials or the company manufacturing the product.
Primary data is a critical component of carbon footprint calculations as it provides the original information on carbon emissions and their sources. Primary data is required in each life cycle stage to accurately and reliably measure emissions.
Secondary data, on the other hand, refers to information based on databases and other statistical generalizations. Unlike primary data, secondary data is not directly sourced from original references but is based on information collected and published by other researchers, organizations, or public sources.
In carbon footprint calculations, secondary data can provide information on the carbon emissions associated with products, services, or processes at different stages of their life cycle, such as raw material production, manufacturing, transportation, or disposal. Secondary data may also include pre-existing emission factors.
2. The scope of the calculation: company, product or project?
In carbon footprint calculations, there are generally three types of assessments: company-specific, product-specific, and project-specific assessments.
Whether it is a product or company-specific calculation, the goal is to build an inventory of the emissions generated. The calculation describes the types of emissions that have occurred and allows for their aggregation.
Company-specific carbon footprint calculation (Scope emissions)
Emission reporting is becoming an integral part of companies’ routine operations. Authorities are tightening the requirements for non-financial reporting, and in the future, companies will be required to report their emissions annually, similar to financial statements.
The most common standard used for calculating corporate environmental impacts is the Greenhouse Gas Protocol (GHG Protocol). The emissions categories defined by GHG Protocol are Scope 1, 2, and 3, which describe a company’s total emissions under three different boundaries, encompassing both direct and indirect activities of the company.
Scope 1: Direct emissions from the company’s own activities.
This emissions category refers to the emissions caused directly by a company’s operations. This includes, for example:
- In-house energy production, such as burning oil for heat generation.
- Internal transportation using diesel or gasoline.
- Manufacturing processes in certain industrial sectors where CO2 is released as a byproduct.
- Potential leaks, such as gas leaks from cooling systems or pipelines.
Scope 2: Indirect emissions from purchased energy.
This category includes all indirect emissions resulting from the purchase of energy by the company, such as electricity, heat, steam, or cooling. The Scope 1 emissions of one company may also be considered as the Scope 2 emissions of another company in the energy production sector.
Scope 3: Indirect emissions from the company’s value chain.
Scope 3 emissions represent indirect emissions resulting from the company’s activities that occur in its value chain, including raw material sourcing, product manufacturing, use phase, disposal, or use by consumers.
Scope 3 emissions are further divided into upstream and downstream emissions. Upstream emissions occur before the company receives the product and utilizes it, while downstream emissions occur after the company has sold the product onward.
Product-specific carbon footprint calculation
We’ve now learned that Company-specific assessments are known as Scopes, and they consider internal activities, purchased energy, and all inputs and outputs of the organization. They cover both direct and indirect emissions from a company’s operations.
Product-specific assessments on the other hand, are guided by ISO standards, and provide a framework for considering the entire life cycle of a product and determining which emissions are relevant for a specific product. These standards often prioritize the calculation of fossil emissions rather than biogenic emissions. For example, emissions from the burning of wood may not be considered, and the focus is mainly on fossil emissions.
It is important to be cautious about the boundaries used in carbon footprint calculations, especially in product-specific assessments. The life cycle of a product can be divided into different stages, such as cradle-to-gate, cradle-to-customer, or cradle-to-grave. Product Environmental Footprint (PEF) initiative aims to standardize the way products’ environmental performance is assessed.
Chain-linked life cycle assessments use the cradle-to-gate boundary, excluding consumption and waste management, as this allows the output of one product to be used as input for another. Consumer behavior and waste management often involve assumptions due to the complexity of tracking individual behavior accurately.
🌾 Helsinki Mills calculated product carbon footprints and launched a Oat Food Generator on their website.
Product-specific assessments involve creating a life cycle inventory
This means calculating all the emissions associated with the production of a product and allocating those emissions to specific products.
From the same production process, multiple product streams, by-products, or waste streams may arise. In such cases, allocation is needed to distribute the emissions between the main product and the by-product or waste. This is often done based on economic allocation principles, where the overall value of the main product and the value of the by-products are considered to determine the emission allocation. Allocation can also be done based on factors such as mass or energy content. Company-specific assessments do not require allocation.
Different boundaries and considerations are made in product-specific assessments regarding which emissions are included in the calculation of a product’s manufacturing.
For example, emissions associated with building an automobile factory may be excluded, and only emissions resulting from the use of transportation vehicles are considered.
Drawing a boundary is a matter of choice, and the boundaries are set as part of the background calculation where emission factors are defined. Standards and common practices guide the setting of boundaries, but ultimately, it is the responsibility of the emissions factor creator to determine the boundaries.
The challenges of life cycle assessment primarily revolve around obtaining comprehensive understanding of what is included in the calculation. While standards define the boundaries, obtaining the necessary information can be challenging.
3. Verification of results
Carbon footprint calculations can be performed by anyone, and they are done using various methods. Transparency in calculation methods is important for credibility.
The most important aspect is to generate numbers that can be reported on an annual basis. Reporting also has its own standards, and often requires clarification on how the data was obtained and what emission factors were used. It is important to refine the results over time as new information becomes available.
Several organizations and initiatives strive to harmonize the methods used to measure and report the carbon footprint of food. The goal of harmonization is to create a consistent and transparent framework that enables meaningful comparison of different food products.
If a company aims to achieve the Science-based Targets initiative goals, the carbon footprint results need to be verified by an external party. Verification is also crucial for public marketing claims. However, for internal use, a company can calculate the carbon footprint without verification.
During the verification process, an external entity reviews the calculation results and input data on which the calculation is based. An expert examines how the data was obtained, assesses its reliability, and verifies the credibility of the results.
Frequently asked questions about carbon footprints
The carbon footprint is calculated by multiplying the activity variable by the emission factor. Initially, an inventory of all emission-generating activities, such as raw materials, transportation, production inputs, and packaging, is formed. Then, all variables are multiplied by their emission factors.
The result is expressed in CO2 equivalents, which is a common measure of all different greenhouse gases.
With the Biocode carbon footprint calculator, calculation is easy because emission factors and conversion of emissions into CO2e are built into the tool. Users only need to input data about their own processes.
Emission factors can be found in various scientific publications and emission factor databases, such as Ecoinvent. Emission factors are also built into digital carbon footprint calculators, including Biocode.
The carbon footprint is constantly changing; it can vary due to changes in production methods, raw materials, or transportation distances, for example. Updates are also continuously made to emission factors and calculation methods as science and modeling behind them evolve. That’s why it’s important to measure the carbon footprint continuously.
For example, in a factory, multiple products are often manufactured, requiring the allocation of factory emissions, i.e., dividing them among the products. Product-specific energy consumption can be estimated, for instance, by determining the total energy consumption of the factory and dividing it by the mass proportions of different products, their economic values, or the time spent in production.