All means of transport (bus, train, tram, car, boat, plane, ...) emit CO2e. So every time you travel, CO2e is released into our atmosphere. CO2e is a greenhouse gas that is released when fossil fuels such as oil, gas or coal are burned. The more CO2e there is in the air, the warmer the earth becomes.

This warming will have and is already having multiple consequences at regional and global scales: changes in temperatures, an increase in the frequency and intensity of extreme weather events, a decrease in certain resources such as water, and rising sea levels. If greenhouse gas emissions do not decrease significantly over the next few years, many areas could become uninhabitable. Global warming is inevitable, but we can still limit it by reducing our greenhouse gas emissions.

According to a 2019 study by UNWTO (the World Tourism Organisation), transport related greenhouse gas emissions from tourism accounted for 5% of total anthropogenic emissions in 2016 and will increase to 5.3% by 2030.

In May 2018, researchers from the University of Sydney also published a study showing that the global impact of tourism is 8% of global greenhouse gas emissions. The study, published in Nature Climate Change, includes transportation, accommodation, food and shopping by travellers.

Contributing financially to climate projects is a voluntary and concrete way of responding to your climate impact and CO2e emissions. By contributing for 100% of the CO2e emissions of your travels, you give us the opportunity to support projects that prevent CO2e emissions, for sustainable socio-economic development. These projects would not exist without your support and without the CO2e contribution system. Many climate projects need your support. Projects proposed by Greentripper meet high requirements to ensure that your contribution really makes a difference.

When you contribute for 100% of your CO2e emissions from accommodations and transportation (car, plane, etc.), you make it possible to reduce, sequester, or avoid the same amount of CO2e emissions in a climate project as those emitted during your journey.

Greentripper guarantees that your contribution for one tonne of CO2e corresponds to:

• one tonne of CO2 that is reduced or avoided through a certified climate project in a developping country
• or one tonne of CO2e that is sequestred in a sustainable project in Europe.

With the carbon contribution, you give us the opportunity to work with NGOs and communities to collectively mitigate climate change and participate in sustainable socio-economic development.

To ensure that your contribution makes a real difference in favour of our climate, Greentripper only supports climate projects that meet the highest requirements.

The concept of carbon offset involves financing projects that reduce, avoid, or capture carbon to offset your carbon footprint. With certified carbon contribution, it means purchasing carbon credits from projects that are certified and are developed in line with the strictest quality criteria.

At Greentripper, we have chosen to replace the term "offset" with "contribution" for several reasons. Firstly, the term "offset" can give the impression that the climate crisis can be solved through simple accounting measures, which, unfortunately, is not the case. Tackling climate change requires a collective, long-term approach involving all sectors. > By using the term "contribution," we acknowledge that our efforts aim to make a positive difference rather than completely eliminating negative impacts. Tackling climate change requires a collective, long-term approach involving all sectors.

By using the term "carbon contribution," we promote active participation in collective carbon neutrality. > We believe in promoting collaboration with our stakeholders. The term "contribution" emphasizes our collective responsibility and encourages engagement from everyone involved. It invites individuals and organizations to join us in making a difference rather than relying solely on offset mechanisms.

This voluntary carbon contribution approach is most effective when combined with efforts to reduce CO2 emissions.

First, it is important to define carbon neutrality. Carbon neutrality is a scientific concept whose definition is given by the IPCC (Intergovernmental Panel on Climate Change): “The situation in which anthropogenic emissions of greenhouse gases into the atmosphere are offset by anthropogenic removals over a given period”. It is therefore a balance between all human-caused emissions and negative emissions, i.e. what can be absorbed by human-managed carbon sinks (forests, soils) or by possible carbon capture and storage technologies.

For its part, ADEME encourages a long-term vision and daily action to contribute to the objective of territorial or global carbon neutrality. Individual organizations are neither, nor can they become, nor claim to be “carbon neutral”.

Greentripper has chosen to stop talking about CO2e neutrality for CO2e contribution related to travel. We believe that the notion of “CO2e Neutrality” still makes sense but only in a global context, meaning, within the framework of 'contributing/participating in collective carbon neutrality,' and when significant efforts have been made to reduce one's carbon footprint beforehand. CO2e contribution is used as a last resort for emissions that could not be avoided.

Aircrafts, cars, and other means of transportation use energy to get to its destinations. This energy comes from the combustion of fossil fuels, releasing CO2e and other greenhouse gases, which contributes to climate change. To give you an idea, 1 tonne of CO2e is emitted by:

• a one way trip from Brussels to New York in economy class
• 6.000 km's by car
• 336 non-vegetarian meals

A tonne of CO2e could be represented schematically by 1/5 of an Atomium ball or by a 200m3 hot air balloon.

There are several types of greenhouse gases (not only carbon dioxide): we can transpose every type of greenhouse gas emission into CO2 equivalents. Bearing in mind that each greenhouse gas has a more or less significant global warming potential in relation to CO2, to determine the equivalence of a tonne of greenhouse gas in carbon credits, a specific coefficient has to be applied to the gas in question to convert the tonne into a tonne of CO2 equivalent. This makes it possible to compare the contribution of these different gases to global warming and to take account of them in efforts to reduce the impact of an organisation or product on the climate.

In the Greentripper calculator we take into account the different greenhouse gases (CO2, but also other greenhouse gases such as CH4 and N2O) which are converted into a CO2-equivalent. That is why we speak about CO2-equivalents and not CO2.

We also take into account radiative forcing which is caused by the condensation trails we see behind an aircraft in flight.

If we want to calculate the full impact of a plane trip, we have to take into account the greenhouse gases from the combustion of kerosene, but also other factors such as the condensation trails. These are the white lines formed by the condensation of the water vapour emitted by aircraft engines at very high altitudes. Independent scientists (Institut Bilan Carbone, ADEME) estimate that with radiative forcing, the impact of the plane’s greenhouse effect is multiplied by 2 compared to greenhouse gas emissions from the combustion of kerosene alone.

The Carbon Neutrality Company says: "The analysis of information we have on the impact of aviation on the global climate system clearly shows that the impact on the climate goes beyond the simple effect of CO2 emissions. All the additional factors have an additional global warming effect. According to all the measurements developed to gauge the impact of aviation, we estimate that an approximate factor of 2 should be applied to the CO2 impact."

Passengers travelling in first class and business class have more space, which means that fewer passengers can take the same plane. Consequently, more CO2e emissions are attributed to first class and business class passengers compared to economy class passengers.

This phenomenon is comparable to cars transporting 1 or 4 persons. Even if these 4 persons are heavier to transport, there is a scale effect which shows that the more passengers in a mode of transport, the fewer the CO2e emissions per passenger.

A plane burns an enormous amount of fuel on take-off and landing. Once airborne, the plane consumes far less per km or per mile travelled. That is why short-distance flights or flights with stopovers are more polluting per km. This means that the average emissions are significantly lower per km travelled for long-distance flights.