1. To estimate greenhouse gas emissions, and in particular CO2, we **calculate the distance between the two airports**, and deduce the amount of kerosene needed.

2. Then, we add a fixed quantity of kerosene to **take into account takeoff and landing**.

3. This mass of fuel oil is multiplied by a fixed factor (from 3.1) to **estimate the amount of CO2 emitted**

4. Then, this quantity is **distributed** over the average number of passengers per flight, depending on the weight corresponding to the planes's class. To infer everyone's share.

There isn't enough land upon which to plant enough trees in order to absorb all the CO2 we emit, so simply planting trees will never be *sufficient*.

It's necessary, ** at first, to reduce our emissions.**

On the other hand, planting trees is a **necessary step**.

In fact, through the process of **photosynthesis**, the tree uses light to absorb CO2 which it uses to grow...and afterwards to produce biomass. The forest is a real **carbon sink**.

There's no longer any time to just limit damage; we have to act!

1. **We are foresters.**

We don't just plant trees, we **take care of them throughout their entire lives.**

2. **We maintain our forests** to ensure the sustainable absorption of CO2.

A poorly managed or non-managed forest can have a negative carbon footprint, if the wood rots.

3. **We promote biodiversity.**

The forest is a complete ecosystem, whose resilience requires the diversity of tree species and varieties.

4. **You're part of the adventure!**

When you plant a tree with EcoTree, that tree belongs to you, as well as its carbon absorption.

Aircraft emissions are not limited to CO2: burning kerosene also produces nitrogen oxides (NOx), which are greenhouse gases, too. In addition, the aircraft produces these gases at a high altitude, where they have a greater environmental impact.

Trees do not absorb NOx, but it is possible to estimate the radiative forcing of NOx, which means the approximate equivalent amount of CO2 that would have to be absorbed to counterbalance the effect of NOx can be calculated.

To be thorough, therefore, a multiplicative factor - generally estimated at a factor of 2 - is applied to the CO2 emitted on its own to estimate the total amount of CO2 that must be absorbed to compensate for all the greenhouse gases emitted by the flight.

Take, for example, a short flight of around 1000 kms - which will last about 2 hours.
First of all, a **fixed factor** of about 95 kms must be added to this distance to take into account ** evasive actions and tactical manoeuvres upon approach**.

To complete this flight, the aircraft will consume **2.7 kg of fuel oil per km**, or about 2.95 tons of kerosene for the trip itself, to which 1.1 tons for take-off and landing must be added, as well as for taxiing between runways and terminals. This gives us a total of 4.05 tons.

This consumption of fuel oil produces CO2 - up to 3.1 kg for each kg of fuel consumed. Therefore, in our example, the aircraft will produce a carbon footprint of 12 tonnes of CO2, of which 75% is produced on the route itself and **25% for the landing and take-off phases (or LTO).**

When it comes to short flights, we consider about 7% of the weight is used for cargo (this figure increases to 26% for long haul flights), which leaves us with 93% left-over for passengers, or about 11 tonnes.

With an average of 150 seats on the type of aircraft used (for short flights), and an average occupancy rate of about 82%, we obtain an average of 123 passengers.
If we divide this evenly over all passengers, we obtain an estimate of **90 kg of CO2 emitted per passenger. **

To be fairer, **a multiplicative factor ** is applied to take into account the fact that business class and first class occupy a larger usable area, and therefore generate a proportionally larger share of CO2.

In the case of long haul flights, the calculation method follows the same pattern, but takes into account different variables, such as the amount of kerosene required for take-off, consumption per km, and the number of passengers in the aircraft.