First, one needs to understand how serious the problem of CO2 emissions is.
Few people know how much CO2 is released during the combustion of one liter of gas or petrol.
The answer is 2.3kg! Think about it for a minute, this is an astounding number.
A car that consumes 8l/100km will release 18,4 kilograms of CO2 per 100km. The average European drives a distance of 20,000km, that is about 3,7 tons of CO2 each year per car.
For plane travel, the problem is worse. One hour of flying per passenger is about 250kg of CO2 per hour.
A round trip New York – Paris (14h) represents 3,5 tons of CO2 per person in economy class. Business class passengers count double as they take proportionately more space in the plane.
For persons who fly, even a couple of times per year, their carbon footprint coming from plane travel will represent quickly more than half of their total carbon footprint.