Measuring product carbon footprint

Examining key considerations that can lead to a reduction in your product’s environmental impact.

The term ‘carbon footprint’ is frequently used in relation to the environmental impact of a particular product, process, or even organisation. This article will focus on what a product carbon footprint is, provide context to the values generated, and discuss the data that is required in order to create a carbon footprint for a particular product, as well as some of the challenges that are likely to be encountered.

What is a product carbon footprint, and why is it important to measure this? A product carbon footprint is a calculation of the estimated total sum of greenhouse gas (GHGs) emissions – ‘CO₂e’ (the ‘e’ stands for ‘equivalent’) – produced during a product’s lifecycle. This makes for a complex calculation so, for the sake of simplicity, emissions for all GHGs are converted to a CO₂e value. If considering how much damage each gas will cause over a 100-year period, methane will do most of its damage in the first ten years, whereas carbon will only have done one tenth of its damage during that time.

An increase in the amount of greenhouse gases in the atmosphere as the result of the burning of fossil fuels is causing climate change, the impacts of which are being felt worldwide – with humanity facing such increasing challenges as extreme weather conditions, rising sea levels and melting polar ice. Many countries and organisations have committed to achieving net zero emissions targets by 2050, in line with the Paris Agreement which was adopted in 2015. An important part of achieving that goal is to understand exactly where emissions are being generated and at what levels, so that they can be reduced or eliminated. This is why calculating product and organisational carbon footprints is becoming increasingly important.

The boundaries of a carbon footprint are usually defined as ‘cradle to gate’ or ‘cradle to grave’. A cradle to gate footprint would consider the emissions that are incurred when extracting and producing raw materials, transporting them to the finished goods manufacturing plant, and the subsequent manufacture of the finished item. A cradle to grave approach would similarly consider the shipping and distribution of the item to the final consumer, but also include its use as well as the impacts of what is likely to happen to that product at the end of its life – for example, being sent to landfill or for incineration. As organisations increasingly aim to transition to a circular economy approach, another analysis – ‘cradle to cradle’ – will become more prevalent, considering how a product or its constituent parts can be kept in use for as long as possible or be reused or reprocessed into new items.

Global warming potential comparison of greenhouse gases
Greenhouse gas	Warming potential in CO2e
Carbon dioxide	1
Methane	25
Nitrous oxide	298
Hydrofluorocarbons	124 to 14,800
Perfluorocarbons	7,390 to 12,200
Sulphur hexafluoride	22,800
Nitrogen trifluoride	17,200
1 kg of methane causes 25 times more warming over a 100-year period than 1 kg of carbon dioxide does. The high short-term global warming potential of methane is being tackled by the ‘Global Methane Pledge’ signed at the COP26 summit. This is looking to reduce global methane emissions by 30 per cent by 2023 which, it is believed, could eliminate 0.2°C of warming by 2050. It is worth noting, however, that globally 11 to 12 per cent of methane is estimated to come from landfill sites, so it is a considerable challenge.

It is important when reporting any carbon footprint information that the scope used is also clearly communicated. Studies have found that most of the carbon footprint for items such as clothing and footwear comes from materials and manufacturing, which would be captured in the cradle to gate model, whereas items consuming electricity during use will still have a considerable impact after their initial manufacture, depending of course on how the electricity is generated. The shipping of finished good around the world by air freight will also significantly increase the footprint of a particular item compared with shipping by sea or road.

In addition, the considerable challenge of what happens to products at end-of-life should be taken into account.

Carbon footprint in context

Published data suggests that the carbon footprint of a ‘typical’ pair of adult’s running shoes would be in the region of 12 to 15 kg CO₂e per pair. This compares with a pair of men’s jeans at around 19 kg and a return economy flight from London to Hong Kong, which would be well in excess of 1 tonne. These are indicative carbon footprints from particular data sets or studies and, of course, within each particular product type there will be huge variations in the carbon footprints, depending on some of the factors discussed in more detail below.

Key considerations

Some of the main areas that will impact on the carbon footprint of particular item include the type and quantity of materials/components used, how they are made, where they are made, how far each item needs to be transported and the mode of transport used. For instance, if an identical process is carried out in one country where the vast majority of energy is generated from coal-fired power stations and in a second country where there is a mix of energy sources, including nuclear and renewable, the process that is being carried out in the second country will be reported as producing a lower carbon footprint.

The heavier an item is, the more likely it is to have a higher footprint, as the emissions associated with each material or component are based on weight.

Another obvious example would be the use of air freight versus sea freight, with one study calculating that shipping by air generates 47 times more greenhouse gas emissions than sea freight does per tonne-mile.

Correct use of data

The data used to calculate a product carbon footprint will be a combination of primary and secondary data. Primary data will generally need to be provided by the organisations involved in the development and production of an item and could include the following:

• sufficient information to accurately identify each material or component
• the weights of each material or component being used
• details of where each material or component is produced, how far it must be transported to the finished goods production site and how it was moved
• information on the distinct production processes which are being carried out at the production site
• waste/scrap percentages generated during production
• energy consumption and energy sources utilised
• the origin and destination ports for shipping finished goods
• finished goods warehouse locations
• the mode of transport used to ship finished goods
• the likely end-of-life scenario.

Most companies will not have records of energy and material flows, which is where secondary data is also required to evaluate the emissions for a particular item or process. Commonly-used sources of secondary data would be: i) lifecycle inventory databases, ii) industry bodies, iii) government publications, iv) regional and national statistics, v) environmental product declarations, and vi) verified carbon footprints.

These sources can be used to determine the carbon footprint of producing a specific item in a particular country or region (taking into account how energy is usually generated in that region), plus the emissions associated with moving it the relevant number of miles to the next downstream production site via the mode of transport used.

Although considerable data is available – either free of charge or through subscription – there are a number of challenges associated with ensuring that this information is reliable and accurate.

Firstly, the data can be very inconsistent. When checking the carbon footprint value for a return flight from London to Hong Kong across a number of different sources, the results varied from 0.7 tonnes all the way up to 4 tonnes, with most being in the region of 1 to 1.5 tonnes (depending on the age and efficiency of the aircraft fleet). Secondly, the data is not necessarily representative, or could be out of date. For example, data available for the production of a particular material may only be available for a particular variant of that material made in one country. This could have a very different footprint to another variant of the material made in another country, which is the one actually being used.

While there are clearly challenges in gathering all of the required data to complete a product carbon footprint, it is still an excellent process to support organisations to understand ‘hot spots’ that can be targeted for emissions reductions, with a reduction in emissions being the ultimate goal of the carbon footprint process.

Longevity

Although many carbon footprints will take into account expected end-of-life impacts incurred in the disposal of a product, they generally do not consider the anticipated life and durability of a product. In SATRA’s view, a product with a slightly higher footprint that is able to last considerably longer than an alternative item could actually be a more sustainable solution. We would always recommend that products are designed to be as durable (and therefore long-lasting) as possible, and we can advise our members on how this can be achieved.

In conclusion

There are already products available on the market in different sectors that are advertised as ‘carbon neutral’ and while much work may have been undertaken to reduce the product’s impact, it is likely in a lot of cases that it is only fully ‘carbon neutral’ due to some degree of carbon off-setting having taken place. However, as organisations transition to a circular economy and better-quality data becomes available, we will increasingly see a lowering of the carbon footprints, which will hopefully ultimately lead to carbon zero products.

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