Carbon footprinting: how it works and how we can help

It’s painfully clear: climate change is here. The recent record-breaking years and both extremely hot summers and winters indicate that the planet really is getting hotter. In their latest report, the Intergovernmental Panel on Climate Change (IPCC) once again showed that we, as humans, drive the current temperature increases. To do anything about it, we need to know what’s the smart thing to do. Fortunately, that’s why we have carbon footprinting.

With the products that we want and the activities that we do, we emit greenhouse gasses (GHGs) that cause climate change. We urgently need to change what we use and how we do things to reduce those emissions. But where do you start if you don’t know what actually causes these emissions? And which actions have the most significant impact?

To effectively manage our emissions, we need to measure them. Carbon footprinting – assessing how much of an impact or ‘footprint’ on GHG emissions our activities have and where those impacts arise – can help us to evaluate how much products and companies affect climate change. These insights are crucial inputs for changing how we manufacture our products and operate our companies, in order to limit further climate change.

What GHG contribute to global warming, and how much?

Greenhouse gases cause climate change to happen. There are thousands of those gases, grouped into one of seven categories. The most common GHGs are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). The gases differ strongly in their potency towards changing climate, the so-called global warming potential (GWP). Sulfur tetrafluoride (SF4) for example, has a GWP of 20.000 times as high as CO2, while methane has a GWP of 30. The GWP is commonly described in terms of CO2 equivalents (CO2-eq). The total contribution of each GHG towards climate change is thus a combination of the amount that is emitted and the GWP of that gas. Despite their relatively low GWPs, CO2, CH4 and N2O account for almost 98% in terms of CO2-eq.

The contribution of greenhouse gases to global climate change in terms of kg CO2e for 2016. Source: https://ourworldindata.org/greenhouse-gas-emissions.
Quick guide: Global warming potential (GWP)

The global warming potential of a greenhouse gas depends on three things:
1. Its radiative ability, i.e. how well the gas can absorb energy
2. Its lifetime, i.e. how long the gas remains in the atmosphere
3. Its indirect effects, i.e. to what extent does the gas increase the formation of other GHGs in the atmosphere.

Over the years, the accuracy of estimating the GWP of GHGs has improved. Several methods are available for calculating this potential. The IPCC provides recent estimates and the most commonly used values in their reports. Since the value of the GWP may differ depending on the source and method used, it is important to understand what value has been used or to select in your calculations.

By default, the GWP is determined relative to the GWP of carbon dioxide. Therefore, we use the unit kg CO2 equivalents (kg CO2e). The GWP of carbon dioxide is always 1, regardless of when it was estimated or what method was used.

A proper carbon footprint considers not just CO2, but also other GHGs. The unit of the final product or corporate footprint is expressed in kg or tons CO2e. You might however come across carbon footprints in kg CO2. These provide much less information on your global warming impact, since no other GHGs than CO2 have been considered.

Linking the global problem to local footprints

GHGs are emitted throughout our global economy. Emissions happen in each country and in many sectors. But not everything we do has the same amount of impact. Some activities and sectors contribute more to global emissions than others. For example, heating houses accounts for almost 11% of total emissions, while waste treatment only accounts for 3%. Each activity has its own emitting characteristics. Carbon footprints help us to understand the characteristic emissions of our company or products.

The contribution of sectors to global climate change in terms of CO2e for 2020. Source: https://ourworldindata.org/emissions-by-sector.

To calculate the carbon footprint of a product or company, we need three components: activity data, emissions factors and the GWP, which we already discussed.

The activity data is an overview of all our activities. For product carbon footprints (PCFs), this overview ideally covers the whole life cycle of the product: from raw material extraction, production and distribution to the use and finally the end of life of the product. For company carbon footprints (CCFs), we gather activity data on 3 levels:

  • Scope 1 – direct emissions from activities of the company or under their control.
  • Scope 2 – indirect emissions from electricity purchased and used by the company.
  • Scope 3 – all other indirect emissions from activities of the company throughout the value chain, that occur from sources they do not control or own.

Of course, it’s not possible to measure every emission when it happens. To turn activity data into information about emissions, you need emission data. Emission data can be found in databases and state how much of each GHG is emitted per unit of activity – for example per kWh electricity used or liter of diesel burned.

Some EFs are transparent, specific and accurate, while others are more generic and ambiguous. Kg CO2-eq per kWh of electricity consumed, for example, is very generic. However, if you know that the electricity came from a natural gas-fired power plant in the Netherlands in 2021, for instance, you might find more specific emission data for the kg of CH4 per kWh. It’s important to use reliable sources for the data. This is why we prefer established LCA databases like ecoinvent for our footprints.

Guidelines and standards help determine what data to collect, which emissions factors to use, where to find the GWPs and how to report a carbon footprint. The most common standards are the ISO 14067 and GHG protocol Product Standard for PCFs and the ISO 14064 and GHG Protocol Corporate Standard for CCFs.

How does a carbon footprint prevent climate change again?

Unfortunately, knowing your carbon footprint will not prevent further climate change in itself. Still, it is important in two ways. First, a baseline carbon footprint allows you to set meaningful reduction targets, and perhaps share them in public initiatives like the Science Based Targets.

Second, carbon footprints are more than just a number. When executed properly, they can provide a detailed overview of where in the life cycle of your product or the value chain of your company most of the emissions occur: the environmental hotspots. With this overview, you can use scenario testing to determine what emissions reduction measures have the most significant impacts. This is a more specific way to reduce the emissions of your products or company and bring your company in line with your targets.

Quick guide: Carbon footprint vs LCA

There are environmental challenges beyond climate change. For example, biodiversity loss, water scarcity and acidification. A life cycle assessment (LCA) is basically a carbon footprint for multiple environmental challenges. The more challenges you consider, the less likely that changes you make in your company shift the environmental burden elsewhere – for instance, if you save energy by switching to a production method that uses more water. The process we follow at PRé for LCAs is similar as for a carbon footprinting, but the results give a much broader understanding of the environmental impact of your company or your products.

Is your carbon on-track?

Understanding your company’s carbon emission sources is crucial nowadays, but we know getting the right insights can be difficult. Looking for support with your carbon footprint challenges? Or are you interested in a full LCA that includes multiple environmental indicators? At PRé, we can help your company get the most valuable environmental metrics and set impactful reduction targets. Take a look at our consulting services for corporate or product footprints.

If you’re looking to calculate your carbon footprint independently, SimaPro can help you with this. Our specialized software provides environmental data of thousands of products and the global warming potentials of hundreds of GHGs, as included in the latest methodology reports from the IPCC. With SimaPro, you can easily identify carbon hotspots and reduction opportunities, which can help your company communicate transparently and collaborate smoothly with suppliers and clients.

Our consultancy services and tools offer a robust, efficient, and future-proof solution for monitoring and reporting your corporate carbon footprint. Starting now can be a great way to drive additional business value and gain a competitive advantage for your company.

Hendrik Oosterhoff

Consultant

“Meeting the needs of current generation, without compromising the ability of future generations to meet their needs”. The quote from the Norwegian prime-minister Gro Harlem Brundtland defined sustainable development in 1987 and, despite being written 8 years before my birth, has been relevant ever since, both to the world and to me. At the moment societies are still struggling to be sustainable and we are putting great pressure at planet Earth’s carrying capacity, endangering the ability of future generations to meet their needs. To relieve the planet from these pressures, I dedicate myself to support green decision making, allowing for real sustainable development to happen and, most important, for future generations that can meet their needs!

Stay up to date with our newsletter

Newsletter Registration

Section

Section

Newsletters *
Conditions *