# Personal ‘carbon calculator’

18th January, 2007

An increasing number of people want to be able to calculate their carbon emissions. We outline the issue and recommend a site which will calculate emissions from your flight.

There has been greatly increasing awareness about emissions of greenhouse gases, which are leading to climate change. This has led to people wanting to calculate their emissions and so, to meet this demand, a number of ‘carbon calculator’ web sites have been set up.Aircraft are the fastest growing source of emissions and a number of sites specialise in this. Our recommended site is ‘Atmosfair’. This is a German site but has pages in english.  The link is given below.While this and other calculators can give a useful guide to emissions, they must not be regarded as precise. The emissions per passenger are based on a number of assumptions and will depend, among others, on the type of aircraft and the fill of the aircraft.

It should be noted that the Atmosfair site gives emissions of carbon dioxide, CO2. But emissions are sometimes expressed in terms of carbon. One tonne of carbon (C) is equivalent to 3.67 tonnes of CO2.

It should also be noted that CO2 is not the only greenhouse gas emitted by aircraft. Emissions at altitude of nitrogen oxides (NOx) and water vapour (H2O) also cause global warming. The effects of NOx and H2O are less well understood than CO2, but it is usually assumed that the effect of all 3 gases is 2.7 times the effect of CO2 alone.

It is also possible to work out an ‘economic cost’ of the emissions. This is significant because it attempts to quantify the cost of the emissions on society as a whole and indicates how much the airlines (or their passengers) ought to pay under the ‘Polluter Pays Principle’.

The official ‘cost of carbon’ is currently £85 per tonne. (This is the source of much debate – the Stern report of Nov 2006 suggests the cost could be much higher.) If one bases the cost of aircraft emissions only on the CO2 emitted, the cost of a tonne of CO2 is then 85 x 2.7 / 3.67 = £63.

‘Atmosfair’ carbon calculator site (click on English language icon on left)