The Environmental Cost of Flying
What is the main greenhouse gas? Most people would confidently say carbon dioxide (CO2) but in fact it is water vapour in the atmosphere that has the biggest greenhouse warming effect. Like CO2, we release water vapour when we burn fossil fuels. This is not normally a concern because most of the water vapour is recycled as rain and does not accumulate in the atmosphere. However planes release water vapour at a high altitude where it can accumulate, and so cause a lot more warming than that caused by the CO2 planes also release. Unfortunately there is much uncertainly on precisely how much more. The emissions per passenger also depend on the altitude of the flight, distance travelled, type of plane and how fully occupied it is. So there are so many different figures out there when it comes to the climate impact of taking the plane.
Climate Care is one of the best known carbon calculators and their calculator doubles the amount of CO2 emitted to take account of the enhanced atmospheric impacts of aviation. On long haul flights this is known to be an under-estimate and some other calculators use higher factors. Below are some example Climate Care emissions per person compared with a rival calculator. The true figure probably lies somewhere between the two.
| Tons CO2 of return flight from London to |
Climate Care |
ChooseClimate |
| Rome |
0.3 |
1.2 |
| New York |
1.5 |
4.2 |
| Los Angeles |
2.5 |
6.3 |
| Sydney |
5.6 |
11 |
To put these in context, excluding flights an average adult in the UK emits around 5 tons per year. So if you have one long haul flight per year, this will quite likely be easily your largest CO2 contributor and mean you have no chance of reducing your emissions to below average.
In my previous article I encouraged you to use a carbon calculator to help you decide on the best actions to reduce your emissions. If you do this, and assuming you want to have the biggest reduction for the least cost, your top priority will hit you in the face: no more holiday flights.
If you want to discuss any of the subjects raised, I am very happy to talk to groups of people. My email address is derek.leatherhead@ntlworld.com. I will also try and reply to emails from individuals, either directly or in a future article.
Derek Smith
Mole Valley Climate Change Awareness