Product carbon footprint is generally defined as a measure of a product’s greenhouse gas (GHG) emissions in terms of carbon dioxide equivalents (CO2e). But how do you calculate a carbon footprint and how can it help anyone make informed purchasing decisions?
What is a Product Carbon Footprint (PCF)?
The Product Carbon Footprint (PCF) measures the greenhouse gas emissions of a product within a specified period of its entire life cycle. It can range from raw material extraction to end-of-life or disposal (i.e., cradle-to-grave) or from raw material extraction to shipment from the manufacturing facility (i.e., cradle-to-gate).
The PCF is considered to be the most well-established method for determining a product’s contribution to global climate change. It is derived from Life Cycle Analysis (LCA) from the 1960s, and was used in the past to evaluate similar products based on certain criteria such as manufacturing costs, energy usage, water consumption, and so forth. Another precursor is the ecological footprint, which was developed in the 1990s and measures a product’s resource consumption (e.g. land and water).
The first mention of carbon footprint in the literature was in 2008 when countries began to acknowledge the urgent need to reduce greenhouse gas to prevent excessive global warming.
Carbon footprinting measures both the direct and indirect greenhouse gas emissions generated by an individual, organization, event, or product. More importantly, it provides the basic metrics necessary that help manufacturers and individuals identify and analyze the carbon footprint of their products throughout the supply chain. To standardize the reporting of greenhouse gas emissions, each greenhouse gas is converted to kilograms of carbon dioxide equivalent (kgCO2e) based on its global warming potential (GWP).
How is the carbon footprint of a product calculated?
Numerous standards have been developed to determine the carbon footprint of a product. The following are the most commonly used:
- ISO 14067 standard – this standard focuses exclusively on climate change when calculating the carbon footprint of products and services. It uses several common metrics in conjunction with the existing ISO for LCAs. Since 2018, it is consideredas an international reference standard for conducting PCF.
- Publicly Available Specification (PAS) 2050 – one of the most widely used standards for calculating the PCF of products and services. The British Standards Institute developed PAS in 2008 and revised it in 2011 (BSI). PAS is widely regarded as the first international carbon footprint standard.
- The GHG Protocol Product Standard – This standard is very similar to the first version of PAS 2050, but includes provisions for public reporting. Additional standards include those for corporate assessments and GHG emission calculations associated with specific projects. The WRI/WBCSD developed this standard, which was published in October 2011.
The ISO 14067 provides more general guidance, whereas PAS 2050 and the GHG Protocol provide more detailed information on reporting requirements. Regardless of which standard you choose, the general process of PCF assessment is described below:
Step 1: Determine the goal and scope of the analysis
You must determine the scope of the carbon footprint analysis (i.e., cradle-to-grave or cradle-to-goal). It also needs to consider the purpose for which the analysis will be used: for submission to a regulatory agency, for a reporting requirement from funders, for the public, or for internal corporate communications.
At this stage, it is equally important that the company knows the direct and indirect emissions of the product being analyzed based on scopes 1-3 of the GHG Protocol.
Step 2. Conduct a product life cycle inventory or life cycle assessment
This involves a comprehensive inventory of all inputs and outputs within the product life cycle. Inputs assessed or inventoried are typically raw materials, inputs, auxiliary materials, and energy, while outputs include products, wastes, or emissions.
Step 3. Convert all GHG emissions (inputs and outputs) to CO2e.
This is the process of converting all GHGs from the life cycle assessment to a comparable unit using their respective emission factor. Each greenhouse gas has its own emission factor or global warming potential (GWP), which can be used to convert them all to carbon dioxide equivalents (CO2e).
Step 4. Analyze the result and evaluate the impact
At this stage, you can calculate the total emissions per unit of product. You can also identify and evaluate which area of your product’s LCA produces the highest carbon emissions.
The result of the impact assessment can determine your company’s next course of action to find a detailed answer to how and where you should avoid, mitigate or offset carbon emissions throughout their operations to become carbon neutral.
Which products have the largest carbon footprint?
According to Our World in Data, animal-based food products generally have a larger carbon footprint than plant-based products. This is according to the 2018 Global Food Systems Study by Joseph Poore and Thomas Nemecek, which covers 38,0000 commercial farms in 119 countries.
In their study of PCF, they found that one kilogram of beef emits 60 kg CO2e, while peas emit only 1 kg CO2e. Lamb and cheese both emit more than 20 kg CO2e per kilogram, while poultry and pork have a smaller footprint at 6 and 7 kg CO2e, respectively. This metric takes into account a product’s various GHG emissions, from land use change to agricultural emissions, such as the use of fertilizers – both organic and synthetic – and methane emissions from animals.
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