Carbon footprint in travel: what is it and why is it a useful concept?

While the idea of carbon footprint was born as a legitimate tool for sustainability research, some people consider it a buzzword that does not carry much meaning. In this article, we argue that the carbon footprint concept is much more than a buzzword and how the idea can be useful for your business.
Carbon footprint – what's that?_ John-o-Nolan_Unsplash
Written by Team Oncarbon
Carbon management platform for air travel, API-first
March 30, 2022

Words have power. A few decades ago, Republican politicians in the U.S. started saying “climate change” instead of “global warming” because it sounded less alarmist. In recent years, terms like “net zero”, “sustainability”, “carbon footprint” and “ESG” have become widely used and gradually made their way into most companies’ policies, websites and PR. Out of these expressions, the phrase “carbon footprint” probably gets thrown around the most – but do you actually know what it means and why it is proving to be such a useful concept?

You may have heard that the term “carbon footprint” first appeared in a British Petroleum (BP) advertising campaign in 2005. However, this is not true. The idea derives from that of an “ecological footprint” – a concept developed in the 1990s by Professor William E. Rees and sustainability advocate Mathis Wackernagel as a legitimate tool for sustainability research. BP, then, used this concept in the campaign in which it asked people to calculate their personal carbon footprint. Allegedly, BP developed this strategy to blame the negative impacts of the plastics industry and fossil fuel companies on the choices of individuals.

Researchers later called this campaign1 ”one of the most successful, deceptive PR campaigns ever.” BP made no attempt to reduce its own carbon footprint – but it did popularize the idea of carbon footprint among consumers, leading to greater discussion on the topic and the creation of multiple carbon footprint calculators.

Carbon footprint – definition

Before discussing why the carbon footprint is a useful concept, we should define what it is and how it differs from the concepts of climate footprint and ecological footprint. These three terms are sometimes used interchangeably, although their meanings are not exactly the same.

A carbon footprint is the total greenhouse gas (GHG) emissions caused by a person, organization, service, product, etc., expressed in carbon dioxide equivalents (CO2e). These emissions are primarily caused by the burning of fossil fuels, deforestation of land, and the production and consumption of food, manufactured goods, materials, wood, roads, buildings, transportation, and other services.

Personal carbon footprint is the sum of emissions resulting from everything we do and consume as individuals – heating homes, traveling, buying goods, eating, etc., measured in tons of CO2 equivalents.

The concept derives from the ecological footprint, a method of measuring human demand on natural capital – the amount of nature needed to sustain people or an economy. It is expressed in global hectares (gha). For example, Qatar has one of the largest ecological footprint per capita, 14.3 gha/pers, while India’s ecological footprint per capita is 1.2 gha/pers. (data from Footprint Network2 2018)

World map of countries by ecological footprint
Photo: ecological footprint by country 2006, source: Wikimedia Commons

The third concept that has evolved from the carbon footprint is the climate footprint – a more comprehensive measure that refers to the totality of greenhouse gasses: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6), although these terms often get used interchangeably.

Carbon footprint in travel industry

The concept of carbon footprint is particularly important for the travel industry, largely because the travel sector is responsible for 8% of global carbon emissions, according to the scientific journal Nature3. Half of those emissions come from transportation – and in 2019, 85% of the CO2 emissions of commercial air travel were from passenger travel.

According to the International Council of Clean Transportation, about 2.4% of global CO2 emissions come from aviation. Together with other gasses and the water vapor trails generated by aircrafts, the industry is responsible for about 5% of global warming.

Personal carbon footprint

There is another concept we should discuss when talking about the definition of carbon footprint – personal carbon footprint. Numerous websites now offer questionnaires where you answer questions about your eating, traveling and shopping habits to determine your personal carbon footprint and compare yourself to others. Of course, climate-conscious individual choices can make a difference, but at the same time, we should all recognize that consumers are not the only ones responsible for greenhouse gas emissions.

As noted above, BP – like other fossil fuel companies – has tried to send the message that individuals should be held responsible for emissions. The revelation of this sham led to skepticism towards the concept of carbon footprint. People wondered if the concept was not an invention of advertisers who wanted to put the onus of climate change on consumers and take it away from manufacturers.

If you type “carbon footprint is a lie” into Google, you will get thousands of results. Most of them focus on the claim that big oil companies “coined the term to blame us for their greed” and argue that “a personal carbon footprint is meaningless.”

Let’s face it – carbon footprint is a complex concept. At the same time, it is the best measure to quantify the impact of an activity, a person, or a country on climate change – and here are five reasons why.

5 reasons why carbon footprint is actually a useful concept

1. A reliable math model

If we accept a common definition of the carbon footprint as the total greenhouse gas emissions expressed in carbon dioxide equivalents (CO2e), we realize it should be an objective measure. It is data – not a biased judgment.

How do you calculate the carbon footprint? In short, you evaluate and combine all the emissions associated with the product, activity or service and focus on how they translate into CO2 equivalents (based on their global warming potential relative to CO2). Global warming potential (GWP) is the heat absorbed by a greenhouse gas in the atmosphere as a multiple of the heat that would be absorbed by the same mass of CO2 (the GWP of CO2 is 1).

If you are interested in calculating the carbon footprint of travel products, read more about the Oncarbon methodology for flight emissions.

2. A universal concept

Because data collection of CO2 emissions is relatively simple, the carbon footprint can become a practical and repeatable metric that can be used as a “baseline” indicator by all types of organizations worldwide. It can be attributed to every product and service – travel, flights, food, clothing, cars, electronic goods and many more.

Of course, some industries and products will require more advanced calculation methodologies that approximate the climate footprint and include a whole range of non-CO2 gasses.

3. It’s easily comparable

Carbon footprint is a measure based on research and data, so it is easy to compare across industries and countries. We can estimate the average carbon footprint of a flight, a pair of shoes, or a MacBook, but also that of a typical American, African, European, and Asian.

CO<sub>2</sub> emissions per capita by country
CO2 emissions per capita by country, source: Statista

4. It’s easy to communicate

When a company decides to calculate the carbon footprint of its goods or services, it’s easy to communicate the results with a simple label added to every product. As an example of this, Oncarbon serves as a verified third-party label for travel products and flights. This way, the carbon footprint information is available for a customer who can then make a conscious choice.

Example of a flight itinerary with CO2 emissions
Oncarbon displays carbon footprint information in a clear and user-friendly way

5. It’s the first step towards lower emissions or even zero emissions

Calculating and communicating carbon footprint is usually the first step for companies that want to become more sustainable and move towards zero emissions. For many products and services, getting to zero emissions isn’t of course easy, but some first steps typically involve, for instance, switching to zero-emissions electricity in production facilities. For a thorough transformation, though, what is typically needed is a revamp of the entire production and supply chain, even a critical eye towards the products they are producing today – something that many companies are understandably still struggling with today.


The concept of carbon footprint is not the silver bullet that will solve all your sustainability problems – but it is a useful measure and a tool for communicating emissions. It is objective because it is based on mathematical principles. It is universally understandable and easy to communicate, and can be used globally for different products, services, companies and countries.

Despite the fact that oil companies once used the concept for their own propaganda, it is much more than “just a buzzword.” It is – and should be – the first step for any company on the road to greater transparency of the environmental costs of the goods they produce and the services they provide. And this transparency is a step towards a better future – without it, it is impossible to define realistic targets and climate strategies and, consequently, to stop climate change.

Learn how you can become more transparent about your travel products’ carbon footprints with Oncarbon. See our demo and learn how we can help you empower your customers to make better travel decisions.

Original cover picture: John O Nolan/Unsplash.

Team Oncarbon
We’re on the mission to show you that we need – and we can – travel more consciously. We bring closer to you the topics of carbon footprint, sustainable travel and aviation, and transparency in emissions reporting.