What impact does the carbon footprint have on us and our environment?

The carbon footprint measures human activity's impact on greenhouse gases (GES). In particular, carbon dioxide, or CO2, emitted by burning fossil fuels (coal, petrol) to produce and meet all our consumption needs.

The planet's temperature has already risen, on average, by 1°C in the 20th century. By 2040, it should continue to increase by 0.8 °C. According to the last report by the UN's Intergovernmental Panel on Climate Change (IPCC), the average temperature on earth could still evolve from 2.6 to 4.8 °C during the 21st century.

To better understand, Dominique Bourg, a climate change philosopher, compares the situation to that of the last ice age. "Barring accidental events, when we go from an ice age to an interglacial age, the average temperature evolves by 1°C every 1000 years. An increase we have experienced in only 40 years, from the 1970s until today!".

This is why in 2015, the Paris agreement, signed by 222 countries at COP21, planned to reduce their greenhouse gas emissions to sustain the temperature at 2 °C compared to the pre-industrial age until 2100. It is an ambitious target. However, it is not enough to prevent wide-scale disruption to our ecosystem and some specialist expect there to be +2°C as soon as 2040.

Wildfires in Australia and California,
Heatwaves in Canada,
Ocean acidification,
Coastal flooding in Japan,
108-day record without a negative temperature at the Pic du Midi (mountain in the French Pyrenees),
Heavy rainfall in Germany and Belgium,
A free fall in biodiversity: 60 % decline in species of vertebrates within 44 years… 

This climate change will, in all likelyhood, lead to the migration of populations. It will intensify air pollution, having a direct impact on everyone's health.

Skiing seems to be the sport the most directly threatened by global warming, but the spectre is in actual fact much broader. The rise in ocean levels and the erosion of beaches will, for example, make surfing much more complicated. A sport as popular and easy to do as running immediately becomes a great deal harder when it involves running at over 30°C.
And what about ice climbing on glaciers? The Sea of Ice (France) is losing up to 30 m a year!  The impact of global warming on biodiversity also has consequences on our sporting habits: hiking or even scuba diving will be a lot less appealing without animals and plant life variety. 

People's average carbon emissions rate is grouped together into the 3 main categories, which we will take into account in the calculation. It is firstly housing, (with 27 %), followed by transport, (25 %), and lastly food (19 %). We divide the remainder of an individual's carbon impact between goods and services, health, education, public services, equipment and clothing.
There are several free calculators for finding out what your ecological footprint is, such as the "Foot print calculator" or "Nos gestes climats" (Our climate actions) by the French Government's Environmental Transition Agency (ADEME).

A carbon footprint is expressed as weight, generally, in kg or tons of CO2 emitted.
Good to know: we calculate the carbon impact of an activity, a product, a company, a territory or a person.
The idea is to add up the different life stages of these entities, likely to emit CO2, such as the energy consumption, resources, transport, purchases, or even eating habits for physical people.

To calculate a product's carbon footprint, Emilie Aubry, climate issues manager at DECATHLON, invites us to observe its entire life cycle:
- the birth of the concept
- production of raw materials,
- product manufacturing,
- transport,
- distribution,
- use,
- end of life.

If we take the example of a T-shirt's life cycle, you will have to take into account water consumption to grow the cotton, the energy required for spinning, weaving, dyeing the cotton and assembling the fabric, etc. You also have to consider the channel it uses during the course of its use: incineration, recycling, etc.
Emilie points out that "depending on the products, there can be numerous very specific sub-steps. What is hard is getting the data from tiers 2 and 3 suppliers". In other words, from the manufacturer's own subcontractors. This is why the ADEME suggests different scenarios to get a clearer picture, allowing companies to formulate hypotheses about their products' CO2 emissions.
Emilie also reminds us that "the challenge is not to have the most accurate possible data, but actually about determining the activities that emit the most CO2 to then conceive of solutions that reduce these". The calculation step is therefore crucial.

The same principle applies to companies as it does to products. E. Aubry specifies: "ideally, we look at all the company's activities: whether they be direct CO2 emissions (or scope 1), energy purchases (or scope 2) and indirect waste (those of a supplier for example, a customer coming to a store, etc., which we call scope 3)". These 3 scopes are the limits upon which companies base themselves to define the calculation of their emissions.
If the ADEME strongly encourages , companies are currently under no obligation to calculate scope 3 and reduce it. Even though these indirect emissions turn out, in many cases, to be an activity's most important CO2 tonnage scope. Conversely, the companies willing to put a figure on it commit to the Science Based Target initiative, supported, in particular, by the United Nations, to limit their impact to 2°C.
To better understand the activities included in the calculation, let's take a random example… DECATHLON.Here are parts of its activity (all scopes included)the company reports CO2 emissions for:

Manufacturing products
Transporting these products
Delivery to the customer when it is e-commerce
Customers' journeys
Employees' journeys
warehouses and stores: waste, energy, construction.

If some of the data can actually be collected, a lot will be based on hypotheses. We can, for example, make a forecast concerning customer journeys using a survey of a representative panel.
There are standard international calculation methods like the "Greenhouse gas protocol" which let you calculate emissions, in particular, from sites, and tools such as Resource advisor, Metrio, Pace, Glimpact, etc. .

These tools allow you, for instance, convert a unit - kWh, L, ton kg, etc. — into a ton of CO2 emitted by multiplying it by an emissions' factor. It will be different depending on the country concerned: China's emission factor, which uses coal power, will be higher than France's, which uses nuclear power. By the end of the calculation, litres of petrol consumed by lorries on the road and the kWh of energy are converted into tons of CO2.
Once the principal source of CO2 emissions is established, we can then go about reducing this impact.

The concept: The concept: give money to an organisation in charge of planting trees on our behalf if we have taken too many flights this summer.Let's be honest, the method essentially consists of stop feeling guilty about not changing our habits. The practice goes so far as simply purchasing carbon credits without knowing how they will be used. It then becomes necessary to analyse the certification of these credits.
Some companies, by the way, would appear to be putting big budgets into supporting reforestation, deploying solar ovens or even carbon capture and storage in the ground. It is commendable, but according to Emilie Aubry, "the concept of offsetting is misleading. Offsetting doesn't exist. In fact, as a company, we contribute. Favouring offsetting over reduction is in actual fact buying a right to pollute. You sequester when unable to reduce emissions".