Does a bigger Southampton airport with less need to drive to more distant airports offset flight carbon emissions?
In its public information displays prior to submission of the original planning application the airport gave an example of routes to Bordeux from Southampton and from Gatwick. Although Southampton Airport has stopped using this argument – because it is nonsense – the myth prevails. So let’s lay that myth to rest in this one simple graphic:
The example destination (Bordeaux) given by Southampton Airport is nearer Southampton than to Gatwick, which means a third of the saving from using Southampton is due to the shorter flight and has nothing to do with driving!
In both cases, flight emissions (SOU 85.30, LGW 92.2) are much larger than car emissions.
The road carbon emissions saving is 15.67 (LGW) – 0.63 (SOU) = 15.04 kg per passenger.
Even if 1 million people chose to drive to Southampton for their flight rather than to Gatwick, the total carbon saving would be 15.04 million kg or 15,040 tonnes.
But the airport estimates an extra 370,000 tonnes will be emitted on average each year as result of expansion. This is 24 times larger than the road emissions saving.
Does a bigger Southampton airport with less need to drive to more distant airports significantly offset flight carbon emissions?
No! 1 million people driving to Southampton rather than Gatwick reduces by just 4% the extra emissions arising from the runway extension.