The practice of calculating carbon footprint is not old, yet it has already changed and adapted to new demands and technologies. Discover the history of carbon footprint measurement in this article.

Humans have always known that their activities had an impact on the Earth and its resources, but it wasn’t until the 1990s that the concept of a ‘footprint’ first emerged. At the time, researchers started talking of our ‘ecological footprint’, which represented our use of resources compared to the Earth’s ability to renew them. Today, this concept is well understood thanks to Earth Overshoot Day, the day when all the resources the planet can produce in a year run out and we begin to live on future resources. This year, Earth Overshoot Day fell on July 28, a few days earlier than in 2021 and almost a whole month earlier than in 2005.

The birth of the carbon footprint

The concept of carbon footprint was born as part of the ecological footprint, as one indicator of our impact on the Earth. But the idea gained popularity in 2003 when oil and gas company BP launched an advertising campaign asking people on the street what their carbon footprint was. The ad encouraged people to calculate their personal carbon footprint – using BP’s calculator – to find ways to reduce it, with the slogan “It’s a start”.

Because of that, the focus of the carbon footprint remained largely on individuals, despite companies (and especially oil and gas companies like GP) emitting much more problematic levels of emissions. In 2015, with the signing of the Paris Agreement, governments were able to analyze precise data about their countries’ carbon footprint, and the focus shifted to companies. Nowadays, much of the public and regulatory scrutiny regarding the carbon footprint is on corporations, with activists regularly denouncing the hypocrisy of campaigns such as BP’s.

The discovery of global warming

Scientists discovered that levels of carbon dioxide in the atmosphere could change the Earth’s climate in the 1800s, when investigating what had caused the Ice Age – that’s when the term ‘greenhouse effect’ was born. At the dawn of the 20th century, Swedish scientists Arvid Högbom and Svante Arrhenius were the first to estimate the amount of CO2 emitted from the burning of coal, and to warn about the warming effect of an increase in emissions. 

But their theories were viewed with much skepticism until the 1950s, as World War II and the Cold War created a need for high military technology, leading to an increase in government funding for science. The scientific community discovered that the mechanisms thought to prevent global warming (such as the ocean’s absorbing effect) were not effective enough, and that emissions had already increased much more rapidly than previously thought. Still, their warnings were ignored as industrialization picked up pace.

It’s only in the 1990s that people started to pay more attention to what scientists were saying about the climate, and to ask their governments for action. Severn Cullis-Suzuki’s passionate speech about climate change at the Rio Summit 1992 is a clear example of this shift.

Corporate carbon footprint measurement

As climate change became a more and more central concern in international conferences, certain pioneer companies began calculating and disclosing the environmental impact associated with their activities or products. Patagonia was one of the first to conduct a survey of its environmental footprint in 1991, and now the company plans to be carbon-neutral by 2025 – much earlier than most others. Since the 2010s, the number of companies calculating and disclosing their carbon footprint has increased dramatically and today, it has become a requirement imposed by regulators or investors in most countries.

The way companies calculate carbon footprint is quite simple: they multiply each of their activities with the ‘emission factor’ of that activity. But the precision of this calculation has evolved greatly in recent years, as more data becomes available. 

In 2001, the Greenhouse Gas Protocol was published, after a decade of development. It established standards and rules for the calculation of carbon emissions according to their scopes: direct emissions (scope 1), emissions from energy use (scope 2) and indirect emissions (scope 3). To this day, the GHG Protocol remains the tool most used by companies to calculate their carbon footprint.

Carbon footprint calculators

Despite being based on a simple formula, carbon footprint calculation is a complex exercise, particularly for companies. That’s why in general, they hire environmental experts or consultants to assess GHG emissions across their operations. But as data and our ability to process it improves, this exercise is becoming easier to automate.

For instance, ClimateTrade offers sector-specific carbon footprint calculators for mobility, airlines and buildings, having digitized the data points included in the GHG Protocol. This means that companies simply have to enter data into the calculator to find out what their carbon footprint is. In the coming years, we expect automated calculators to grow more precise and more specialized in different sectors, becoming the preferred option for companies.

However they conduct their carbon footprint calculations, companies then need to have the result audited to ensure accuracy, before they can report it to regulators and take measures to reduce and offset their impact.