Ebbe a csapdába már én is beleestem (hosszú számolgatások után). Az egyik fő probléma ezzel, hogy az autó a Föld felszínén, míg a repülő pedig kilométerekkel a felszín felett bocsátja ki a káros anyagokat. Fent a hatása sokszorosa a lentinek a Föld felmelegedését illetően. Kb. ez a lényege:
What's an 'aviation multiplier'?
The impact of planes on the climate is complicated and not perfectly understood. The CO2 emissions are straightforward enough, but plane engines also generate a host of other "outputs", including nitrous oxide, water vapour and soot. At flying altitudes in the upper troposphere and lower stratosphere, these outputs produce a range of climatic effects, multiplying the plane's environmental impact. For example, nitrous oxide causes the formation of ozone — a greenhouse gas that warms the local climate — but at the same time undergoes reactions which destroy methane, thereby removing another greenhouse gas from the atmosphere.
Even more complicated is the impact of soot and water vapour, which together can cause contrails (vapour trails) and in cold air can lead to the formation of cirrus clouds. The science surrounding this topic is not yet rock solid, but researchers believe that contrails add to the greenhouse effect – especially at night, when their tendency to stop heat escaping from the Earth isn't offset by their tendency to reflect incoming sunlight.
Today, most experts favour an aviation "multiplier" of around two. In other words, they believe that the total impact of a plane is approximately twice as high as its CO2 emissions. The exact multiplier, however, will always depend on the individual plane, the local climate and the time of day.