UPDATED
May 29, 2008

This paper was originally put in the public domain in early May 2008. Since then we have received a number of comments and questions. All three air travel emissions calculator developers were invited to comment on the paper. Atmosfair and TRX Travel Analytics have sent us detailed comments and raised a number of interesting discussion points. Therefore we have decided to revise the document to include the most important comments.

The goal is to use this paper as a discussion document in order to facilitate feedback from experts in the field and in order to gain more clarity about the issues discussed here.

You can send your comments to anja.kollmuss@sei-us.org

The full paper can be downloaded here.

The Stockholm Environment Institute announces the release of the first of two papers on emissions calculations from air travel.

Carbon Offsetting & Air Travel
Part 1: CO2-Emissions Calculations

Anja Kollmuss & Jessica Lane

The paper examines the key factors that have to be taken into account when calculating air travel emissions for the purpose of carbon offsetting. This paper first gives a brief overview of three emissions calculators which were chosen because they are among the most comprehensive currently available:

The paper then examines the aircraft parameters that are needed to calculate emissions on a per person basis and describes how each of the three calculators accounts for these parameters. The parameters discussed are:

1. Aircraft Model

2. Flight Profile and Flight Distance

3. Cargo on Passenger Flights

4. Seat Occupancy Rate (Load Factor)

5. Seat Class

The final section of the paper analyzes emissions calculations for flights between three city pairs, and compares the results of the three emissions calculators to each other as well as to the UK’s Department for Environment, Food and Rural Affairs (DEFRA) multiplier for air travel emissions calculations.

The full paper can be downloaded here.