Air flights - what is the overall pie chart situation?

I’ve just been to a seminar on air travel and the figure quoted for the total global contribution of air travel to the total carbon emissions was a mere 2% as opposed to 25% from road traffic in Bristol. In addition, domestic heating, industrial emissions and road travel were said to be about 1/3 each. Are these figures correct, and in which case how much less air travel emissions would be achieved by making leisure and business travel more restricted? Suppose we restricted air travel to family occasions or heads of government only - how many tonnes of CO2 would be saved compared to, say, switching all commuters from car to public or active transport? Where are our efforts best concentrated in terms of the overall pie-chart for the planet?

Thanks for this, really interesting question. Our community has pulled together research about this and has found that the UK government only reports on national emissions with there being little information about international footprints. That means flight emissions are commonly reported at a national level, including emissions from take off and landing rather than emissions from the whole flight. It seems this is the case in this particularly case. A more realistic air travel emissions have been calculated in our Low Carbon Transport Challenge (shared below) as 7% of total GHG emissions (international and national), so it really does matter if we’ve not taking flights.

In terms of overall pie chart for the planet check out the community created guide to reducing personal carbon emissions, there is a good breakdown there.

More input from others of course always welcome!!!

@TinaFOSBR I see the 2% figure a lot so I think it is pretty credible for total global emissions from aviation (for example https://www.atag.org/facts-figures.html) . However, bear in mind that air travel is a luxury that only a small fraction of the global population can currently afford. According to Boeing, 80% of the world’s population have never taken a single flight (https://www.cnbc.com/2017/12/07/boeing-ceo-80-percent-of-people-never-flown-for-us-that-means-growth.html)

If you live in the UK, you are probably already part of that small fraction that can afford to fly and air transport accounts for about 6% or 7% of UK emissions.

Flying from London to New York uses about 0.9 tonnes so if you are trying to keep your personal CO2 emissions under 2.5 tonnes, then cutting out that flight is a very big step in the right direction.

To add another dimension, the paper below compares the global heating impact caused by different forms of transport over varying time horizons (5, 20, 50 years). Over the short term flying has a 4 times greater climate impact than driving a car (per passenger-km) because of the ozone and cirrus clouds planes generate. Looking at air freight its even worse at ~40 times greater than an HGV per kg freight-km.

Remember these numbers represent efficiency. A return flight from London to Toronot is about 7,120 miles which is nearly equal to the average distance travelled per car in the UK according to MoT data in 2017.

Given the scale of the climate crisis we need to enact every change that can significantly reduce our impact. Driving and flying both fit into this category so we should reduce both.

https://pubs.acs.org/doi/full/10.1021/es9039693

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Thanks Chris - this very helpful indeed!